Migrate assets in the /SF/Editor/Resources/ to improve build size.

Anything in a /Resources/ folder gets added into a Unity build, even ones for strictly editor side use like SF. Using the Build Report Tool, all the textures and meshes adds like 430kb or so to it, which could be an issue for web builds since download size can be important.

An alternative is to use /Assets/Editor Default Resources/ - see http://docs.unity3d.com/Documentation/ScriptReference/EditorGUIUtility.Load.html - however it does mean it loses the appeal of being self-contained in the one SF folder. =(