Version 20231227-0 release

[jj1bdx]

• Documentation changes
• 20231227-0: Made the following changes:
  • Split class PilotPhaseLock from FmDecode.
  • Removed submodule readerwriterqueue.
  • Re-introduced DataBuffer from commit 49faddb.
  • PhaseDiscriminator now contains NaN-removal code.
  • Introduced accurate m_pilot_level computation for PilotPhaseLock.
  • Introduced enum PilotState and the state machine for more precisely showing ster
    eo pilot signal detection and the signal levels.
  • Removed buffer option -b and --buffer finally.
• Included PRs: Split class PilotPhaseLock from FmDecode #54 DataBuffer: roll back to std::queue version again #55 Add stabilized state to the stereo pilot detection signs #56 Remove buffer option -b #57

[jj1bdx]

LGTM, all tested.