Add forgotten APIchanges entry for probesize2.

Update some git hashes.
Fix standalone compilation of the WebVTT decoder.
avfilter/vf_pullup: 2nd try to workaround gcc 4.4.3 bug on arm

The first try failed to work with some build flags

The gcc version affected is very old and unmaintained AFAIK thus i made no
attempt to report this to the gcc developers.

The workaround is pushed as it may still affect users and does affect one
fate client

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>