Support 4k AVC-Intra in mov.
avcodec: Add little-endian G726 decoder

Fixes part of Ticket1955
suggested by Roman.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat: Use G726LE decoder for Sun AU files

fixes ticket #1955 as suggested by Roman.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
lavf/riff: Fix a comment.

FourCC aivx refers to (Sony) XAVC, not (Panasonic) AVC-Intra.
Spotted by Kieran Kunhya and Vincent Olivier.
Fix decoding of G.726 in AIFF.

Fixes ticket #1973.