This make _cogl_framebuffer_blit take explicit src and dest framebuffer
pointers and updates all the texture blitting strategies in cogl-blit.c
to avoid pushing/popping to/from the the framebuffer stack.
The removes the last user of the framebuffer stack which we've been
aiming to remove before Cogl 2.0
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 598ca33950a93dd7a201045c4abccda2a855e936)
38921701e5