[proposal] osx build: remove dependency on Carbon

This is just a proposal - there may be other reasons that Carbon is still enabled in the OS X builds. Open to any feedback.

The only real remaining dependency I found was SetSystemUIMode() which has can be simply replaced by NSApplication:setPresentationOptions.

NB: I also tried to update scripts/osx/template/emptyExample.xcodeproj but my Xcode 5 installation seemed to re-write the entire project file (I assume it was automatically upgraded) so the diff was *way* larger than necessary. Leaving that out for now.

With this patch applied, I can successfully link and run a trivial demo against the non-Carbon openFrameworks build.