Added comments to events

PropertyGrid knows update, if Control object has been moved.
Merge remote-tracking branch 'origin/master' into PropetyGrid
Made Trackable unmoveable
Merge remote-tracking branch 'origin/master' into PropetyGrid
Made customUserEvent useable in propertyGrid
Merge remote-tracking branch 'origin/master' into PropetyGrid

Conflicts:
	Editor/Controller/EditorController/PreviewController.cs
unnecessary commit
Merge remote-tracking branch 'origin/master' into PropetyGrid
added comments for ElementSelection controller and connected classes
Merge remote-tracking branch 'origin/master' into PropetyGrid
Merge branch 'master'