Added the GLEW GLFW and OpenGL libraries

These are needed to get the GLFW platform independence layer added.
Fixed FindGLEW attempting to use a debug library blindly
Removed some OS X lines that aren't needed
Add the OS interface class

The event dispatching leads to TODOs until the event system is in place.
main.cpp has been modified to create a window and loop through OS events.
The created window is making an OpenGL 3.0 GLFW_OPENGL_ANY_PROFILE window.
Merge branch 'feature-glfw' into develop