Glow:- Added FramebufferObject and FramebufferObjectSession (unlike most other GL objects, a FramebufferObject doesn't have a "default" object, so binding to zero can mess things up, the window system FramebufferObject might be ID = 2 for example).
- Debug, only perform error checking in debug (else it's too slow).
- Texture, added an IsBound function which is used by FramebufferObject (attaching a texture to a framebuffer can't use an already bound texture).
- VertexArrayObject, added error check in destructor
- Added make_unique (until we've got C++14 support).