DATV demod: added audio
Implemented audio decoding. Also removed the full screen option that does not return correctly to the previous display.
Other changes and fixes
- Perseus: fixed cold start flawed init sequence
- PlutoSDR: recognize networked devices
- FreeDV: internal FreeDV library to facilitate packaging
- Fixed some constness in qrtplib
- Fixed bug in Channel Analyzer deserialization. Fixes issue #314.