tsdemux: Remember requested seek rate and use it

The new seek handling re-creates the segment time information once it
has enough information after a seek.

The problem was that we'd completely ignore the requested rate. So store
that and use it in the newly created segment.

https://bugzilla.gnome.org/show_bug.cgi?id=694369
mpegtsmux: avoid using clipped out buffers

If a buffer was entirely clipped out (ie, it's out of the segment
entirely), we'll end up with a NULL buffer, which we don't want
to process/dereference.
pesparse: Demote a Warning

We actually now know what to do ... have a log message :)
codecparser: Make warnings more meaningful

By stating whether we don't have enough data or it's a corrupted
packet
mpegtsdemux: Add more flag debugging for PES and TS packets

Helps with debugging issues. And also remove unused variable (opcr)

This will also allow us in the future to properly detect:
* random-access location (to enable keyframe observation and
  potentially seeking
* discont location (to properly handle resets)
* splice location (to properly handle new stream changes)
ladspa: initialize debug category earlier

You know, before it's used.
mpg123: Remove dead assignment

harder ? :)
asfmux: Various debug argument fixes

mainly G_GUINT16_FORMAT to ... the right type (guint32 or guint8)
tsdemux: HDV only has mpeg 1 audio layer 2

Set that accordingly on the caps
Update spec file to be current
uvcv4l2_mjpegdemux: Unmap buffer

https://bugzilla.gnome.org/show_bug.cgi?id=699517
uvch264_mjpgdemux: Don't unmap/unref buffer if it's pushed out as-is
uvch264_mjpgdemux: Remove duplicated variables
celt: remove, replaced by opus.
Fix URIs in REQUIREMENTS
mpegvideoparse: do not update caps when bitrate changes

https://bugzilla.gnome.org/show_bug.cgi?id=705035
dvdspu: artifacts when rendering clipped spu

https://bugzilla.gnome.org/show_bug.cgi?id=705039
mpegdefs: Simplify PCR/PTS/DTS => GST conversion macros

We know we will not overflow 64 bits, therefore just use direct
multiplication/division instead of the scale method (trims usage from
50 instruction calls to 2/3).
mpegtspacketizer: More AFC flags

I should have put those in a previous commit. sorry :(
tsdemux: Flush out pending data on EOS

Ensures downstream elements (like decoders) really get all the data