QSV: merge latest changes from trunk.



git-svn-id: svn://svn.handbrake.fr/HandBrake/branches/qsv@5729 b64f7644-9d1e-0410-96f1-a4d463321fa5
QSV: add support for qsv_h264 to the new avformat-based muxers.



git-svn-id: svn://svn.handbrake.fr/HandBrake/branches/qsv@5730 b64f7644-9d1e-0410-96f1-a4d463321fa5