Rc 141_3 changelog

-waterfall dynamic range is restored for 'scale by median' option

rc140 overall changelog vs rc139:

- prevent displaying vertical lines in waterfall at low level of incoming audio signal for 'Scale spectrum by median value' option
- waterfall timestamp is moved to option for any mode but "JT9+JT65", can be optionally shown on right side of the waterfall
- improved FT8 decoder efficiency and sensitivity
- fixed AutoSeq processing of the CQ messages transmitted by user without grid. Affects 1-st counter, own frequency recognition and some other parts of the code, important patch escpecially when using nonstandard or compound callsign.
- changed a little New DXCC priority exceptions
- fixed long lasting bug on Grid retrieving from log when incoming call with report is received
- added FT8 GFSK signal simulator
- added support for unpacking WWROF contest exchange messages
- Grid button in tab2 shall generate message with grid if first callsign in the message is nonstandard one
- implemented basic functionality of FT4 mode
- FT4 QSO shall be logged as mode MFSK / submode FT4 into wsjtx_log.adi and via TCP command. UDP log QSO command goes with mode FT4 and shall be parsed properly by an interacting software.
- optional AGC compensation functionality is implemented for FT4 mode
- improved FT4 decoding
- patch: occasional repeat decoding of the partially received interval is eliminated
- FT4 partial interval decoding implemented
- improved time synchronization at decoding of the partially received interval for all modes
- default value for TX delay is changed from 0.2 to 0.1 sec
- first part of compound callsign shall be used for prefix recognition if both parts have equal length
- LoTW users list is updated, cty.dat file is updated to version CTY-2914
- ALLCALL.TXT file is updated to 97476 callsigns using latest LoTW activity data
- installation package is built with the latest Hamlib changes as of October 4th, 2019 and previously made modifications