Merge pull request #70 from DeVaukz/glfw

Add support for building and running on OS X.
Makes to work with Awesomiun 1.7 in Linux Ubuntu 13.10
Merge pull request #74 from Zardoz89/glfw

Makes to work with Awesomiun 1.7 in Linux Ubuntu 13.10
Fixed linux builds

The CMake file was errantly setting GLEW_LIBRARY in the linux section. This was causing a failure in find_package(GLEW). The setting to a dummy value was moved to the Mac section as Mac doesn't use GLEW.