Merge branch 'master' of https://github.com/Unity-Technologies/ScriptableRenderLoop into Branch_RTRefactoring

# Conflicts:
#	ScriptableRenderPipeline/HDRenderPipeline/HDRP/Camera/HDCamera.cs
#	ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/RenderLoopSettings/RenderPipelineSettingsUI.cs
#	ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/RenderLoopSettings/SerializedRenderPipelineSettings.cs
#	ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipeline/FrameSettings.cs
#	ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipeline/RenderPipelineSettings.cs

ScriptableRenderPipeline/Core/CoreRP/ShaderLibrary/Shadow/Shadow.hlsl

     #define SHADOW_OPTIMIZE_REGISTER_USAGE   0
 #endif
 
+#if SHADOW_OPTIMIZE_REGISTER_USAGE == 1
+#   pragma warning(disable : 3557) // loop only executes for 1 iteration(s)
+#endif
+
 #include "CoreRP/Shadow/ShadowBase.cs.hlsl"	// ShadowData definition, auto generated (don't modify)
 #include "ShadowTexFetch.hlsl"						// Resource sampling definitions (don't modify)
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/RenderLoopSettings/RenderPipelineSettingsUI.cs

         public RenderPipelineSettingsUI()
             : base(0)
         {
-            
+
         }
 
         public override void Reset(SerializedRenderPipelineSettings data, UnityAction repaint)

ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipeline/FrameSettings.cs

         public bool enableTransparentObjects = true;
 
         public bool enableMSAA = false;
+        public MSAASamples msaaSampleCount { get; private set; }
 
         public bool enableShadowMask = false;
 
             aggregate.enableTransparentObjects = srcFrameSettings.enableTransparentObjects;
 
             aggregate.enableMSAA = srcFrameSettings.enableMSAA && renderPipelineSettings.supportMSAAAntiAliasing;
-            if (QualitySettings.antiAliasing < 1)
-                aggregate.enableMSAA = false;
             aggregate.ConfigureMSAADependentSettings();
 
             aggregate.enableShadowMask = srcFrameSettings.enableShadowMask && renderPipelineSettings.supportShadowMask;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/RenderPipeline/RenderPipelineSettings.cs

         public bool supportsForwardOnly = false;
 
         // Engine
-        public bool         supportDBuffer = false;
+        public bool supportDBuffer = false;
-        public MSAASamples  msaaSampleCount = MSAASamples.None;
+        public MSAASamples msaaSampleCount = MSAASamples.None;
         public bool         supportsMotionVectors = true;
         public bool         supportsStereo = false;