FlightGear - Flight Simulator FGAddon

PAR: revert to passing an absolute path to 'play-audio-sample'

This works again since today, namely since SG commit 22779ee2c and FG
commit e7594f4687 on 'next' (doing so didn't work between FG commit
8853fded29 dated 2021-07-27, and these commits). Using an absolute path
here has two avantages:

- the add-on will work again with older versions of FlightGear such as
the 2020.3 release (the previous way, added very recently, required
FG commit 60ff405efc from 2022-08-19);

- access using an absolute path is (slightly!) faster than letting
SimGear's ResourceManager iterate over all providers until it finds
the AddonResourceProvider.

ATCChatter: revert to passing an absolute path to 'play-audio-sample'

This works again since today, namely since SG commit 22779ee2c and FG
commit e7594f4687 on 'next' (doing so didn't work between FG commit
8853fded29 dated 2021-07-27, and these commits). Using an absolute path
here has a few avantages:

- the add-on will work again with older versions of FlightGear such as
the 2020.3 release (the previous way, added very recently, required
FG commit 60ff405efc from 2022-08-19);

- in this particular case, this makes the code simpler (because we use
Nasal's directory() function which doesn't know about [addon=...]
resource path prefixes);

- access using an absolute path is (slightly!) faster than letting
SimGear's ResourceManager iterate over all providers until it finds
the AddonResourceProvider.

Aerotow Everywhere: v1.6.0 (for PlayeRom)

Airspeed-Horsa:Fix key bindings to allow for AI tow plane

Aerotow Everywhere:Initial Commit (for PlayeRom)

SpokenGCA: replace settimer() calls with maketimer()

settimer() has been disabled in add-ons since FGData commit
e39ebd79e3505c4a; use maketimer() instead.

ATCChatter: use a single timer object

Instead of creating a new timer object for every sample, create a single
one at module scope and restart() it in nextChatter() with the
appropriate delay.

PAR: replace settimer() calls with maketimer() and make sound work again

- settimer() has been disabled in add-ons since FGData commit
e39ebd79e3505c4a; use maketimer() instead.

- Use addon.resourcePath() to specify the path to the directory
containing the sound files; this allows the add-on to still work on
'next' where fgcommand("play-audio-sample", ...) doesn't work with
absolute paths anymore (this is so since FG commit 8853fded2953959;
see the discussion starting at [1]). This will also work on 2020.3
when SimGear commit 8febf6b9f58e9 and FlightGear commit 60ff405efcc
are cherry-picked to the release/2020.3 branch.

[1] https://sourceforge.net/p/flightgear/mailman/message/37694083/

ATCChatter: use the AddonResourceProvider for 'play-audio-sample'

Indirectly use the [addon=...] special syntax (that makes the SimGear
ResourceManager go through the AddonResourceProvider) in order to specify the
files fed to the 'play-audio-sample' FGCommand. This makes the add-on work
again: since FG commit 8853fded29539593, it wasn't possible anymore to use
'play-audio-sample' with an absolute path (the SimGear ResourceManager may be
changed in the future to allow absolute paths that can be validated for read
access; see the discussion around [1]).

[1] https://sourceforge.net/p/flightgear/mailman/message/37695530/

ATCChatter: replace remaining print() with logprint() and bump version number