Add support for right control key on OS X

Related to #401
Fix mouse moved event on OS X when dragging the cursor (close #277)

Conflicts:
	src/sfml/window/OSX/SFOpenGLView.mm
Remove dead code
Improve reactivity of setMousePosition on OS X (fix #290)

Conflicts:
	src/sfml/window/OSX/SFOpenGLView.h
	src/sfml/window/OSX/SFOpenGLView.mm
Improved mouse events on OS X (close #213, related to #277)

Conflicts:
	src/sfml/window/OSX/SFOpenGLView.mm
Fix typos