M17 support is Linux only
The build of the M17 modem library is failing unexpectedly in Windows therefore M17 will be supported in Linux only
Other changes and fixes
- AIS: NMEA sentences must end with CR/LF. Issue #1333. PR #1342
- Darken ValueDials when disabled. PR #1331
- Map: Fix capitalisation of Radiosonde so settings are found. Fixes #1318. PR #1320
- USRP: Catch all exceptions from set_rx_agc. PR #1315
- GLScope and GLSpectrum removed extraneous call to cleanup method. Fixes #1295
- Update to sdrangel-windows-libraries with UHD 4.2.0. PR #1314