doc/encoders: alphabetically list the encoders

Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
doc/decoders: document libopus decoder

Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
Do not list libshine like a main option in configure's output.

It is listed as an enabled external library if applicable.
tak_parser: properly mark packets as key frames

Signed-off-by: Paul B Mahol <onemda@gmail.com>
udp: Fix receiving large udp packets

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