Cleaned up unused usings

ScriptableRenderPipeline/Core/Camera/CameraSwitcher.cs

-using System.Collections;
-using System.Collections.Generic;
 using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering

ScriptableRenderPipeline/Core/Camera/FreeCamera.cs

-using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 

ScriptableRenderPipeline/Core/Debugging/DebugActionManager.cs

-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering

ScriptableRenderPipeline/Core/Debugging/DebugItemHandler.cs

-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using UnityEngine;
 using System;
 

ScriptableRenderPipeline/Core/Debugging/DebugItemUI.cs

-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering
 {

ScriptableRenderPipeline/Core/Debugging/DebugMenuManager.cs

 using System;
 using System.Linq;
 using System.Reflection;
-using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 

ScriptableRenderPipeline/Core/Debugging/DebugMenuState.cs

-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using UnityEngine;
 using System;
 

ScriptableRenderPipeline/Core/Debugging/DebugMenuUI.cs

-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering

ScriptableRenderPipeline/Core/Debugging/DebugMenuUpdater.cs

-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering
 {

ScriptableRenderPipeline/Core/Debugging/DebugPanel.cs

-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using UnityEngine;
 using System;
 

ScriptableRenderPipeline/Core/Debugging/DebugPanelUI.cs

-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using UnityEngine;
 using System;
 

ScriptableRenderPipeline/Core/Debugging/Debugging.cs

-using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 

ScriptableRenderPipeline/Core/Debugging/Editor/DebugMenuEditor.cs

-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 using UnityEditor;
 
 namespace UnityEngine.Experimental.Rendering

ScriptableRenderPipeline/Core/Debugging/Serialization/DebugItemStateBool.cs

-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering
 {

ScriptableRenderPipeline/Core/Debugging/Serialization/DebugItemStateColor.cs

-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering
 {

ScriptableRenderPipeline/Core/Debugging/Serialization/DebugItemStateFloat.cs

-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering
 {

ScriptableRenderPipeline/Core/Debugging/Serialization/DebugItemStateInt.cs

-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering
 {

ScriptableRenderPipeline/Core/Debugging/Serialization/DebugItemStateUInt.cs

-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering
 {

ScriptableRenderPipeline/Core/Inputs/InputRegistering.cs

-using System.Collections;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using UnityEngine;
 
 namespace UnityEngine.Experimental

ScriptableRenderPipeline/Core/Singleton.cs

-using UnityEngine.SceneManagement;
-
 namespace UnityEngine.Experimental.Rendering
 {
     [ExecuteInEditMode]

ScriptableRenderPipeline/HDRenderPipeline/Debug/DebugDisplay.cs

-using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using System;

ScriptableRenderPipeline/HDRenderPipeline/Debug/LightingDebugPanel.cs

-using System.Collections;
-using System.Collections.Generic;
-using UnityEngine;
+using UnityEngine;
 using System;
 
 #if UNITY_EDITOR

ScriptableRenderPipeline/HDRenderPipeline/Editor/HDRenderPipelineInspector.cs

 using System;
 using System.Reflection;
-using System.Linq.Expressions;
 using UnityEditor;
 using UnityEditor.Experimental.Rendering;
 

ScriptableRenderPipeline/HDRenderPipeline/HDRenderPipeline.cs

 using System.Collections.Generic;
 using UnityEngine.Rendering;
 using System;
-using System.Linq;
 using UnityEngine.Rendering.PostProcessing;
 using UnityEngine.Experimental.Rendering.HDPipeline.TilePass;
 

ScriptableRenderPipeline/HDRenderPipeline/Lighting/Volumetrics/HomogeneousFog.cs

-using System;
-
-#if UNITY_EDITOR
-    using UnityEditor;
-#endif
-
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 {
     [ExecuteInEditMode]

ScriptableRenderPipeline/HDRenderPipeline/Lighting/Volumetrics/VolumetricLighting.cs

 using System;
 using UnityEngine.Rendering;
 
-#if UNITY_EDITOR
-    using UnityEditor;
-#endif
-
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 {
 

ScriptableRenderPipeline/HDRenderPipeline/Material/Builtin/BuiltinData.cs

-using UnityEngine;
-
 //-----------------------------------------------------------------------------
 // structure definition
 //-----------------------------------------------------------------------------

ScriptableRenderPipeline/HDRenderPipeline/Material/LayeredLit/Editor/LayeredLitUI.cs

 using System;
 using UnityEngine;
-using UnityEngine.Rendering;
 
 using System.Linq;
 
 
         private class StylesLayer
         {
-            public readonly Color[] layerColors = 
+            public readonly Color[] layerColors =
             {
                 Color.white,
                 Color.red,

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Editor/BaseLitUI.cs

 using System;
 using UnityEngine;
-using UnityEngine.Rendering;
 using UnityEngine.Experimental.Rendering.HDPipeline;
 
 namespace UnityEditor.Experimental.Rendering.HDPipeline
             public static GUIContent ppdMinSamplesText = new GUIContent("Minimum steps", "Minimum steps (texture sample) to use with per pixel displacement mapping");
             public static GUIContent ppdMaxSamplesText = new GUIContent("Maximum steps", "Maximum steps (texture sample) to use with per pixel displacement mapping");
             public static GUIContent ppdLodThresholdText = new GUIContent("Fading mip level start", "Starting heightmap mipmap lod number where the parallax occlusion mapping effect start to disappear");
-            public static GUIContent perPixelDisplacementObjectScaleText = new GUIContent("Lock with object scale", "Per Pixel displacement will take into account the tiling scale - Only work with uniform positive scale");            
+            public static GUIContent perPixelDisplacementObjectScaleText = new GUIContent("Lock with object scale", "Per Pixel displacement will take into account the tiling scale - Only work with uniform positive scale");
 
             // Vertex displacement
             public static string vertexDisplacementText = "Vertex displacement";
             ppdMinSamples = FindProperty(kPpdMinSamples, props);
             ppdMaxSamples = FindProperty(kPpdMaxSamples, props);
             ppdLodThreshold = FindProperty(kPpdLodThreshold, props);
-            perPixelDisplacementObjectScale = FindProperty(kPerPixelDisplacementObjectScale, props);            
+            perPixelDisplacementObjectScale = FindProperty(kPerPixelDisplacementObjectScale, props);
 
             // vertex displacement
             enableVertexDisplacement = FindProperty(kEnableVertexDisplacement, props);
                 ppdMinSamples.floatValue = Mathf.Min(ppdMinSamples.floatValue, ppdMaxSamples.floatValue);
                 m_MaterialEditor.ShaderProperty(ppdLodThreshold, StylesBaseLit.ppdLodThresholdText);
                 //m_MaterialEditor.ShaderProperty(perPixelDisplacementObjectScale, StylesBaseLit.perPixelDisplacementObjectScaleText);
-                m_MaterialEditor.ShaderProperty(depthOffsetEnable, StylesBaseLit.depthOffsetEnableText);                
+                m_MaterialEditor.ShaderProperty(depthOffsetEnable, StylesBaseLit.depthOffsetEnableText);
                 EditorGUI.indentLevel--;
             }
 

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Editor/LitUI.cs

 using System;
 using UnityEngine;
-using UnityEngine.Rendering;
 using UnityEngine.Experimental.Rendering;
 using UnityEngine.Experimental.Rendering.HDPipeline;
 

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LtcData.DisneyDiffuse.cs

 using UnityEngine;
-using UnityEngine.Rendering;
 using System;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LtcData.GGX.cs

 using UnityEngine;
-using UnityEngine.Rendering;
 using System;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline

ScriptableRenderPipeline/HDRenderPipeline/Material/Unlit/Editor/BaseUnlitUI.cs

 using System;
 using UnityEngine;
-using UnityEngine.Rendering;
 
 namespace UnityEditor.Experimental.Rendering.HDPipeline
 {

ScriptableRenderPipeline/HDRenderPipeline/Material/Unlit/Editor/UnlitUI.cs

 using System;
 using UnityEngine;
-using UnityEngine.Rendering;
 
 namespace UnityEditor.Experimental.Rendering.HDPipeline
 {

ScriptableRenderPipeline/HDRenderPipeline/Material/Unlit/Unlit.cs

 using UnityEngine;
-using UnityEngine.Experimental.Rendering.HDPipeline;
 using System;
 
 //-----------------------------------------------------------------------------

ScriptableRenderPipeline/HDRenderPipeline/SceneSettings/Editor/CommonSettingsEditor.cs

-using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reflection;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 {

ScriptableRenderPipeline/HDRenderPipeline/SceneSettings/SceneSettings.cs

-using System.Collections;
-using System.Collections.Generic;
 using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline

ScriptableRenderPipeline/HDRenderPipeline/SceneSettings/SceneSettingsManager.cs

-using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 

ScriptableRenderPipeline/HDRenderPipeline/ShaderConfig.cs

 using UnityEngine;
-using UnityEngine.Rendering;
 using System;
 //-----------------------------------------------------------------------------
 // Configuration

ScriptableRenderPipeline/HDRenderPipeline/ShaderPass/ShaderPass.cs

 using UnityEngine;
-using UnityEngine.Experimental.Rendering.HDPipeline;
 using System;
 
 //-----------------------------------------------------------------------------

ScriptableRenderPipeline/HDRenderPipeline/Sky/HDRISky/Editor/HDRISkyEditor.cs

-using System.Collections;
-using System.Collections.Generic;
 using UnityEngine;
 using UnityEditor;
 

ScriptableRenderPipeline/HDRenderPipeline/Sky/HDRISky/HDRISkyRenderer.cs

-using UnityEngine.Rendering;
-
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 {
     public class HDRISkyRenderer : SkyRenderer

ScriptableRenderPipeline/HDRenderPipeline/Sky/ProceduralSky/Editor/ProceduralSkyEditor.cs

-using System.Collections;
-using System.Collections.Generic;
 using UnityEngine;
 using UnityEditor;
 

ScriptableRenderPipeline/HDRenderPipeline/Sky/ProceduralSky/ProceduralSkyRenderer.cs

-using UnityEngine.Rendering;
-
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 {
     public class ProceduralSkyRenderer : SkyRenderer

ScriptableRenderPipeline/HDRenderPipeline/Sky/RuntimeFilterIBL.cs

 using UnityEngine.Rendering;
-using UnityEngine.Experimental.Rendering.HDPipeline;
 using System;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline

ScriptableRenderPipeline/HDRenderPipeline/Wind/ShaderWindSettings.cs

-using System.Collections;
-using System.Collections.Generic;
 using UnityEngine;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline

ScriptableRenderPipeline/LightweightPipeline/Editor/ShaderGUI/LightweightUnlitGUI.cs

 using System;
 using UnityEditor;
 using UnityEngine;
-using UnityEngine.Rendering;
 using UnityEditor.Experimental.Rendering.LightweightPipeline;
 
 public class LightweightUnlitGUI : ShaderGUI

ScriptableRenderPipeline/LightweightPipeline/LightweightPipeline.cs

 using System;
-using System.Collections.Generic;
 using UnityEngine.Rendering;
 using UnityEngine.Rendering.PostProcessing;
 using UnityEngine.XR;