wavparse: pass on tags from upstream if there are any

Don't just ignore upstream tags from e.g. an ID3 tag before
the .wav data, pass them on downstream.

https://bugzilla.gnome.org/show_bug.cgi?id=729223
rtpjpegdepay: sanity check for NULL qtable

Can happen (at least in crafted stream)

Coverity 1208778
rtpvrawpay: guard against pathological "no space" condition

Even if one woul hope one pixel can fit in a MTU, ensure we do not
overwrite a buffer if this is not the case.

Spotted while looking at Coverity 1208786
mpegaudioparse: remove dead code

A stricer check is already done earlier, and integer overflows
do not seem possible here.

Coverity 1139675
flacdec: remove dead code

For 8 bit width, we always have depth==gdepth==width==8.

Coverity 1139678
v4l2: Correctly map RGB32 format

In v4l2 specification, RGB32 has the alpha, or pading, first, not last.
See http://linuxtv.org/downloads/v4l-dvb-apis/packed-rgb.html .

https://bugzilla.gnome.org/show_bug.cgi?id=540941
oss4: fix a missing unlock and a return-only-when-assertions-enabled

Spotted on the side while looking at another issue.
oss4: remove dead mixer code

This was partly removed in the port to 0.11. If still needed,
it's still there in the history.

Coverity 1139687
speexdec: remove dead code

fpp can never equal 0 here, or the loop would not execute at all.
Zero fpp was possible before as the loop condition was allowing
it specifically, but no more.

Coverity 1139681
qtdemux: trivial typo fix
qtdemux: guard against invalid frame size to avoid division by 0

Coverity 1139690
qtmux: handle 0 size packets without dividing by 0

Coverity 1139691
avimux: refuse caps with invalid framerate

Coverity 1139701
matroska: catch failure to map buffer

Avoids dereferencing NULL.

Coverity 1139712
matroska: do not return GST_FLOW_OK if we did not get a buffer

Coverity 1139714 (which will likely come back in another guise,
as the _read_init call can have a failing _map)
matroska: do not try to call gst_pad_query_default on a NULL pad

gst_matroska_parse_query can be called explicitely with a NULL pad.
If we reach this point with a NULL pad, fail the query.

Coverity 1139715
videoflip: add missing break in switch

Coverity 1139755
matroska: do not lose the top bits when writing a > 32 bit value

Coverity 1139806
matroska: blindly fix writing variable length negative values

Spotted while fixing something else in the area.

Nothing calls this with a negative value.
flacdec: fix theoretical integer overflow

This code isn't actually used at the moment, unsure if I should
just remove it or not...

Coverity 1139811