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
muxer: use inline for almost empty functions
WEBUI: cosmetic changes with add icon for tabs

I also add icon named tv_cards.png but i do not know how add this icon
to tabs named: TV adapters.

Please correct the more well-known for adding the icon to the tabs.
WEBUI: use tvCards icon for TV adapters