Still not complete, using GLEW for OpenGL extensions, and an X
implementation that uses more recent API to create OpenGL contexts
including OpenGL 3/4 if the required extension is present. This also
used XLibs directly for interaction, rather than going through Xt.

It needs a little more work to actually hook up something that will
render to the context, but it shows a great black window right now!

Change-Id: Ida0be9f2e9dc11ba3253ffd18cffa2e983ec954e