TINYGL: Changed the way textures are disposed.
Textures are now marked as disposed and then cleaned up afterwards when the function cleanup is called. (this is needed in order to defer blit calls without making them crash because a texture has been disposed before the frame ended)
TINYGL: Added a call to tglPresent in GRIM engine
Note: I'm not exactly sure that's the right place to put it but as for now it was the only place that allowed the frame counter to be rendered after everything
TINYGL: Added some getter functions to FrameBuffer
TINYGL: Finished basic implementation of BlittingDrawCall.