Started on profiler and cleanup

-Added basic profiler that returns the number of draw calls and number
of vertices rendered.
-Cleanup. We shouldn't include "using namespace ..." in headers. This
headers are then included in many different places, sometimes even
recursively. So in the end it causes many bugs. I removed "using
namespace enigma_user" from GL3context.h, and it caused problems in
several seemingly unrelated files which I had to fix.