A new update is available on the beta branch on Steam. The OpenGL2 and OpenGL4 graphics driver classes have been merged into a new class called simply "OpenGLGraphicsDriver".
OGG support has also been added. The following header search paths must be added to C++ projects:
..\..\Source\Libraries\libogg\include
..\..\Source\Libraries\\libvorbis\include
..\..\Source\Libraries\\libvorbis\lib