forced 3.2 context, code applied from https://github.com/mclark4386/SFML/commit/7ab7ca90283b3277675ef92d9c3119a9081c41dd

Conflicts:
	src/SFML/Window/OSX/SFContext.mm
Added setMouseGrabbed to Window and WindowImpl interface
added a Window::grabMouse implementation for OS X
added window grabbing mouse impl for X11
Some comment adjustments to WindowImplCocoa
include gl3.h on Mac in OpenGL.hpp
Merge branch 'grabcursor'
include gl3.h on os x
Merge branch 'coreprofile'

Conflicts:
	src/SFML/Window/OSX/SFContext.mm
only send when delta > 0
Merge branch 'grabcursor'
RenderTarget::push/popGLStates() are empty for now, a possible solution in the future might be to switch OpenGL contexts? I don't need it, so I'm not going to spend time on it right now. :(
disabled some pre-core resets in RenderTarget::resetGLStates()
made RenderTarget::applyBlendMode play nicely with modern OpenGL
updated GLEW to newer version, only on osx for now
added a default shader to RenderStates
made graphics module play nicely with OpenGL core. Currently quite ugly at some places, and vertex cache is disabled
Merge branch 'graphicswithcore'
commented out a bunch of resetGlState code to not mess up my existing 3D state. Something has to be done with this in the future probably
query GL_LINK_STATUS and not GL_COMPILE_STATUS after compiling to not fail when linking has actually been successful