UDP/RTP audio with PCMA/PCMU
Implemented PCM A-law (PCMA) and mu-law (PCMU) codec processing when sending audio via UDP/RTP. Also impemented decimation on audio to be able to accomodate 8000 S/s sample rate. Standard PCMA or PCMU is 8 bit 8 kHz sample rate. This provides lighter network payload than the only 16 bit linear direct processing available before. Also PCMA and PCMU are standards commonly accepted by browsers for playback using WebRTC.
See: https://github.com/f4exb/sdrangel/blob/master/sdrgui/audio.md for the audio settings
See: https://github.com/f4exb/sdrangel/wiki/Networking-audio for the feature usage
Other changes
- SoapySDR: fixed some GUI issues