Added using new versions of libav audio and video decoding and encoding functions.
Added conversion/resampling functionality.
Added using of libav audio fifo buffer.

Works with latest git master of libav.

Signed-off-by: Michel Verbraak <info@1st-setup.nl>
libav: allow to use libavresample >= 1.1.0
transcode: move some logs from debug to trace
Merge pull request #2 from tvheadend/master

merge