Conflicts:
	configure.ac

Avoid caps copy and leaks

Remove const from the GstCaps.
Plug some GstStructure leaks

https://bugzilla.gnome.org/show_bug.cgi?id=672880

Discard caps event when checking for and counting various tag events,
and remove all testing of 8 bits depth in 16 bits width format since
it no longer exists.

... such as always setting pad caps and providing needed caps fields.

... particularly since each incoming pad has a distinct format.

... even if some SPS/PPS has not passed by yet.

... to avoid trying to take a non-recursive lock twice.

Don't log with the ERROR category when we are stopping because we are shutting
down.

Fixes: https://bugzilla.gnome.org/show_bug.cgi?id=672824

Chain up to the base class start method so that metadata is properly tagged.
Remove an unused variable.

fixes: https://bugzilla.gnome.org/show_bug.cgi?id=672813

.. or turn the overlay off by setting alpha to 0.0