matroskamux: Fix constantly growing used uid list

Moves the used uid list to the class to avoid having it grow forever.

https://bugzilla.gnome.org/show_bug.cgi?id=723269
cairooverlay: add support for RGB16

https://bugzilla.gnome.org/show_bug.cgi?id=723289
gst: Don't use endianness-specific S8 audio format

It does not exist.

https://bugzilla.gnome.org/show_bug.cgi?id=723331
v4l2: Remove obsolete definition GST_V4L2_MISSING_BUFDECL

The only use was removed by 9edc0c0365f79ab07ff2e65461c6696e3931a3f0

https://bugzilla.gnome.org/show_bug.cgi?id=723446
flacenc: order format in template caps by preference

To minimise risk of bad fixation, though audioconvert
at least should be smart enough to avoid it.
deinterlace: do not try set deinterlace method if passthrough is enabled

Fixes an issue with progressive content and unsupported video formats
for the deinterlace method.

https://bugzilla.gnome.org/show_bug.cgi?id=719636
osxvideo: Fix libtool usage

--tag=CC is needed for static build
effectv: fix doc section of revtv element