2.6.0

The main impetus for this release is a complete reorganization of the build system to enable Digital RF to run with Python 3 and on Windows. Major changes include:

• Python 3.5+ compatibility (excluding 'gr_digital_rf' since GNU Radio does not support Python 3 yet).
• Windows compatibility, including conda packages.
• Automated CI testing with revamped Python tests using 'pytest'.
• Python package available on PyPI (for 'pip' install), including binary wheels for Linux, OSX, and Windows.
• Python 'gr_digital_rf' packaged with 'digital_rf' since we no longer require GNU Radio to build (dropping Digital RF C Sink support).
• New 'thor' options:
  • Output channel settings including rational resampling, frequency shifting, and channelizing
  • Clock source (10 MHz ref) and time source (PPS) split out from sync_source
  • Clock lock check with nolock option to skip
  • LO source/export
  • Tuning arguments
  • DC offset and IQ balance
• Updated sounder example transmit script with some 'thor' features.
• Matlab reader fixes for recent data format and packaging as a Matlab Toolbox.
• Various bug fixes and improvements (see commit log for full list of changes).