FlightGear - Flight Simulator FGAddon

Citation X: bug fixes in flight director

* Nasal/flightdirector.nas (get_ETE): the ETE values were displayed incorrectly.
Factorize the code.

Citation X: avionics improvements by Sascha Reißner

- ADF frequencies are now displayed correctly
- ADF frequencies range changed (Honeywell RMU-850 have 100-1800 kHz)
- Squawk can be set
- Transponder receives the altitude from the altimeter
- Transponder is by default set to mode ALT (mode S)
- ID button on RMU triggers the ident mode
- the 4th button on left side toggles the mode between STBY and ALT
but there is no display to show the actual mode!
- both RMUs control the same transponder

click sound

Citation version 4.0.0: new multiplayer protocol and some bug fixes

The multiplayer protocol in this version is incompatible with previous versions of the aircraft
but this only affects people who have renamed /usr/share/games/flightgear/AI/Aircraft/Citation
in order to use the detailed model to see remote Citations.

* Set /sim/multiplay/protocol-version to 2: require at least fgfs 2017.2.
* Use absolute property names of the local fgfs for rendering, i.e. /sim/rendering/*, even in
animations of a remote Citation.
* Use normal property names in all animations instead of the sim/multiplay/generic/ ones.
* Models/Citation-II.xml (nasal/load):
- alias the sim/multiplay/generic/ properties to the normal ones.
- Add the following properties to the protocol:
controls/human-models: attempt to show humans over mp.
gear/gear[0..2]/rollspeed-ms: animate wheels over mp.
gear/gear[0..2]/compression-m: animate compression over mp.
- Use short (4 bytes incl. tag) instead of int (8 bytes incl. tag) for voltage properties,
systems/electrical/outputs/*.

The attempt to show humans over mp fails for now because the animation requires additional
properties not initialized in the property subtree of the remote Citation, namely
/sim/model/crew/pilot[0..1]/*, /sim/model/pax[0..6]/*. They are declared in
Citation-II-common.xml, which is not loaded when the Citation is a remote aircraft (only
Models/Citation-II.xml is loaded). This probably affects the walker, too.

fix bugs reported by clm76

J3Cub: Fix issue with gear changeover, cleanup variants, start of state re-factoring

'skinnable' class manages mouse events

Mouse events managed by 'skinnable' class

Pup 0.31.0: Reimplement electrical system using property rules

Pup 0.30.5: Fix checklist conditions and bindings for pitot heater