bindRenderBuffer was setting framebuffer instead of render buffer. Added new public flag checkAllErrors,
if set it will print any glGetError errors after each call. This is slow, but helps a lot when debugging problems.

Change-Id: I7450df5c7822d3f6c47127d4f7a163696838fb68
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>