Add support for E-AC-3 audio

[Former user]

See: http://forum.serviio.org/viewtopic.php?f=7&t=3992

Serviio doesn't distinguish between AC3 and EAC3 (used for example by French HD terrestrial TV). So it's impossible to transcode this Codec when the devoice doesn't support it natively. Another solution can be to add a " forceATranscoding" option (in the same way the is today a " forceVTranscoding" option) but in this case all AC3 will be transcoded even if not nedded.

Pierre