Move remaining files out of SerializableGraph folder and remove a few unused files

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/MaterialGraphEditWindow.cs

         string m_Selected;
 
         [SerializeField]
-        SerializableGraphObject m_GraphObject;
+        GraphObject m_GraphObject;
 
         [NonSerialized]
         bool m_HasError;
             }
         }
 
-        SerializableGraphObject graphObject
+        GraphObject graphObject
         {
             get { return m_GraphObject; }
             set
                 selectedGuid = newSelectionGuid;
 
                 var textGraph = File.ReadAllText(path, Encoding.UTF8);
-                graphObject = CreateInstance<SerializableGraphObject>();
+                graphObject = CreateInstance<GraphObject>();
                 graphObject.hideFlags = HideFlags.HideAndDontSave;
                 graphObject.graph = JsonUtility.FromJson(textGraph, graphType) as IGraph;
                 graphObject.graph.OnEnable();

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Implementation/GraphObject.cs

 
 namespace UnityEditor.Graphing
 {
-    public class SerializableGraphObject : ScriptableObject, IGraphObject, ISerializationCallbackReceiver
+    public class GraphObject : ScriptableObject, IGraphObject, ISerializationCallbackReceiver
     {
         [SerializeField]
         SerializationHelper.JSONSerializedElement m_SerializedGraph;

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/Graph.meta

+fileFormatVersion: 2
+guid: 20d63795c62940409089af61496db945
+timeCreated: 1513348939

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/MaterialGraphChange.cs.meta

-fileFormatVersion: 2
-guid: 53af639a9c00c2740ba7f23e2b38cf34
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/MaterialGraphChange.cs

-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using UnityEditor.Graphing;
-
-namespace UnityEditor.ShaderGraph
-{
-    public class ShaderPropertyAdded : GraphChange
-    {
-        public ShaderPropertyAdded(IShaderProperty shaderProperty)
-        {
-            this.shaderProperty = shaderProperty;
-        }
-
-        public IShaderProperty shaderProperty { get; private set; }
-    }
-
-    public class ShaderPropertyRemoved : GraphChange
-    {
-        public ShaderPropertyRemoved(Guid guid)
-        {
-            this.guid = guid;
-        }
-
-        public Guid guid { get; private set; }
-    }
-
-    public class LayerRemoved : GraphChange
-    {
-        public LayerRemoved(Guid id)
-        {
-            this.id = id;
-        }
-
-        public Guid id { get; private set; }
-    }
-}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/SerializableGraph.meta

-fileFormatVersion: 2
-guid: e47723110397ff04388ed94332cd6208
-folderAsset: yes
-DefaultImporter:
-  externalObjects: {}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/Graph/GraphChange.cs.meta

-fileFormatVersion: 2
-guid: cbfac7ed81744ca281be9e21eae861c7
-timeCreated: 1505620762

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Interfaces/Graph/GraphChange.cs

-using System;
-
-namespace UnityEditor.Graphing
-{
-    public abstract class GraphChange {}
-
-    public sealed class NodeAddedGraphChange : GraphChange
-    {
-        public NodeAddedGraphChange(INode node)
-        {
-            this.node = node;
-        }
-
-        public INode node { get; private set; }
-    }
-
-    public sealed class NodeRemovedGraphChange : GraphChange
-    {
-        public NodeRemovedGraphChange(INode node)
-        {
-            this.node = node;
-        }
-
-        public INode node { get; private set; }
-    }
-
-    public sealed class EdgeAddedGraphChange : GraphChange
-    {
-        public EdgeAddedGraphChange(IEdge edge)
-        {
-            this.edge = edge;
-        }
-
-        public IEdge edge { get; private set; }
-    }
-
-    public sealed class EdgeRemovedGraphChange : GraphChange
-    {
-        public EdgeRemovedGraphChange(IEdge edge)
-        {
-            this.edge = edge;
-        }
-
-        public IEdge edge { get; private set; }
-    }
-}