Benchmark program and decimators optimization
New benchmark program to test decimators. Run sdrangelbench -h to display all options. This supports issue #166 to take a decision on further developments. While tuning the benchmark some optimizations on decimators could be made based on the benchmark results. Not tremendous improvements still on an average usage one can expect a few % improvement on CPU load.
Change of GUI font
Unify font usage across distributions using Liberation Sans (proportional) or Liberation Mono (monospace). Included font files in GUI resources (sdrgui) which should ensure a look and feel independent of the O/S or Linux distribution. One can expect a slight change in this look an feel however it is very similar to the default that was used previously. It could only look a bit more sleek.
Other changes and fixes
- fixed SSB modulator channel un-registration. This fixes issue #167
- AM demodulator: fixed delayed squelch
- NFM demodulator: fixed squelch tail cutting useful transmission in some cases
- SSB demodulator: improved AGC threshold (squelch like) to better fit useful begin and end of transmission
- Scaling engine improvement on tick spacing calculation that should prevent text collision in some cases
- DSD demod: allow audio rates integer multiples of 8k other than 48k