Version 1.8.7

[mickybadia]

Hello,
I have just pushed a stable version 1.8.7, whose most notable change at this point is going to be the compatibility with Python 3.10 for most of you. Now that it is everywhere, it was about time I corrected that. Now done and tested.

Otherwise the majority of the work was done on CPDLC, to reach full coverage of the official CPDLC message element type list (ICAO doc. 4444).
Although less to do with FG, work was also done to provide CPDLC to FSD sessions. It is supported by Hoppie's ACARS network, used everywhere on those kinds of networks (VATSIM, IVAO...) and supported by planes. FSD was also given an integrated access to FGCom-mumble, as nothing prevents them from using it---and I would certainly recommend! (free RDF with that even)

Related to CPDLC in pratice, I also added a departure clearance prep feature. See if you like it.

On a sadder note, magnetic declination had to become a manual local setting as the previously used NOAA back-end retrieval is no longer free.

[mickybadia]

...aaand a bug found in there: "change tower height" cheat in solo.
Corrected for next version, to come after more tests on the FSD stuff.