WIP - GLRenderer

-Added a GLRenderer.  This will accept a scene of data and create the GL
representation of that scene and it will be responsible for rendering
it.
-The PreviewWidget owns a renderer
-Added a getObjects function to the Scene to get a list of objects.
-Added QtDebug to the Utils header in debug only builds
-Added non-qt specific DEBUG and RELEASE defines in the makefile
-GLRenderer is barebones