VIGS: Add framebuffer and temporary texture pool

VIGS: Add framebuffer and temporary texture pool

In order not to waste host GPU resources we now
have 2 OpenGL object pools - for temporary textures
and for framebuffers. These used to be allocated for
every surface, but now we allocate only one object
per distinct format, i.e. one
object per (width, height, format) tuple

Change-Id: Ie63e571045a2477043e8e08da3a50765523e54fc
Signed-off-by: Stanislav Vorobiov <s.vorobiov@samsung.com>