[Cogl] wip/cogl-1.14 heads up

[Robert Bragg]

For reference I've pushed a wip/cogl-1.14 branch which cherry picks a
*lot* of work from Cogl master to create a new 1.x branch that doesn't
break any stable APIs. In fact it also avoids changing several
experimental APIs that are currently used by Clutter and Mutter so we
can release a 1.13.2 snapshot as soon as possible and hopefully get
GnomeShell tested against it. We can look at updating some of these
experimental apis afterwards.

Initially the plan had been for cogl-1.12 to be the last 1.x branch
before Cogl 2.0 but it looks like we were a bit optimistic. Since lots
of people are depending on the Cogl 1.x api and developers are
continuing to want to extend the API with new features we would rather
not have a branch that is too divergent from master since that will
become harder and harder for us to maintain.

This new cogl-1.14 branch has been been brought into line with master
except wherever master has deleted deprecated api or made api changes
and so cherry picking new apis between both master (which is focused
on 2.0 developments) and cogl-1.4 should now be pretty straight
forward.

I've asked Neil to review the wip/cogl-1.14 branch and if he's happy
with it then I'm planing to release a 1.13.2 snapshot and rename the
branch to cogl-1.14. Of course anyone else is also welcome to double
check this branch too.

Once we have a 1.14 branch I'd also like to look at landing Adel's
_buffer_age patch we have in bugzilla, and we'd also be looking to get
the frame-synchronization patches landed on this branch as well as
Daniel's fencing apis. (B.t.w I already have a rebased
wip/frame-synchronization branch which I can look at pushing soon)

kind regards,
- Robert