Added control of threading model, setting default to SingleThreaded to avoid crash  associated with mixing useCursor(false) and multi-threading.
Added control of threading model, setting default to SingleThreaded to avoid crash 
associated with mixing useCursor(false) and multi-threading.


git-svn-id: 23b6355f2bb369032457de4eb5f713ee134f73a8@6834 16af8721-9629-0410-8352-f15c8da7e697

joevandyk/osg,joevandyk/osg,joevandyk/osg,joevandyk/osg,joevandyk/osg