Version 2.3.0

• Added support for mixers. It is now possible to produce audio streams
  combined from several input channels. Both mono and stereo mixing is
  supported. Usage example is provided in config/mixers.conf. All
  mixer-related parameters are documented in config/reference.conf.
• Added build options for 64-bit ARM architectures, like Odroid C2.
  Please use PLATFORM=armv8-generic when compiling.
• Fixed a long-standing bug in RTL sample processing, which caused some
  samples to be processed twice. If you were annoyed by these regular
  clicks in NFM audio every 125 ms, they are now gone.
• Reduced CPU usage on x86
• Some code restructuring and cleanups
• Added several configuration file examples for typical real-life
  scenarios. They are placed in config/ subdirectory. rtl_airband.conf.example
  file has been moved to config/reference.conf. It is meant to be a reference
  for all supported config knobs together with their description. This is
  still an interim solution before some more readable and understandable
  documentation gets written.