Moved to using NSOpenGLView.
Fixed OS X enter/leave full screen triggers.
Removed use of cursor rectangles.

Poor use of cursor rectangles broke Lion full screen and led to rect
reset loop.  Cursor image is now updated only with the existing
enter/exit detection NSTrackingArea.

Fixes #339.
Fixes #375.
Merge remote-tracking branch 'upstream/master' into travis-osx