[Mac] CGDisplayBounds signature now matches Mac ABI

This resolves a crash in CGDisplayBounds when running through monokick.
[Mac] Remove call to NewEventHandlerUPP

NewEventHandlerUPP fails to load when running through MonoKickstart. It
appears that this function is only used for old PPC systems that had
trouble with function pointers - sample code online indicates that we
do not need to call this.
[Mac] Removed unused CarbonGLNative.cs