Renamed DropItem to OnDropObjects - Object is more consistent with what's being supplied as parameter
Removed OnDrop - Runtime classes should not have any concept of DragAndDrop as it's an editor only feature
Send entire Object array instead of one object at a time - The user might be interested in whether the objects are part of the same operation
* made RemoveNode function virtual
used for example when a graph wants to block a delete
* switched order of remove function and destroy function.
target.RemoveNode was always getting a null value
Moved NodeEditorWindow.ShowNodeContextMenu to NodeEditor.AddContextMenuItems
Moved NodeEditorWindow.ShowGraphContextMenu to NodeGraphEditor.AddContextMenuItems
Moved NodeEditorWindow.CreateNode to NodeGraphEditor.CreateNode
Fixed NodeEditorGUILayout.PortField being inconsistent with Ports drawn by NodeEditorGUILayout.PropertyField
Removed obsolete NodeEditorGraph.GetNodePath
Preferences can now be saved with a custom key, and custom default settings can be specified.
Other changes:
XNodeInternal renamed to XNodeEditor.Internal
NodeEditorWindow.graphEditor exposed as public
