deinterlace: fix off-by-one crash when downstream caps contain a list of framerates

https://bugzilla.gnome.org/show_bug.cgi?id=719544
Revert "matroskamux: Use the running time for container timestamps, not buffer timestamps"

This reverts commit b3aa8755fe07639f22e4104f4932d769d6c9075a.

We are already using the running-time because they were placed on the
buffers with gst_collect_pads_clip_running_time(). Arguably it would be
better to not modify the incomming buffers but collectpads seems to want
to use absolute timestamps from the buffers for finding the best buffer
(this can be changed with a custom compare function..).
matroskademux: don't leak TOC chapter list
rtpg726pay: don't leak encoding_name string

https://bugzilla.gnome.org/show_bug.cgi?id=722159
osshelper: Don't leak fd when getting card name

https://bugzilla.gnome.org/show_bug.cgi?id=722163
avimux: write correct blockalign for vbr audio

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=720659
avimux: reset some more audio pad data when needed