- correct several errors on the deblocking accross slice boundaries.
- add support for deblocking_filter_idc==2 which means no deblocking accross slice.
- correct MMCO with multiple slices.
5 more streams from H264 conformance suite are now correctly decoded.
patch by (Loic <lll+ffmpeg >< m4x dot org>)
Originally committed as revision 3786 to svn://svn.ffmpeg.org/ffmpeg/trunk