FlightGear - Flight Simulator FGAddon

- Update autobrake animations in 3D cockpit
- Revise keys description in help menu
- Correct JSBSim error due to excess <product>
- Add comm-radios instrument (re-enable ATIS)
- Instead of polling at 2hz, switch to setlistener for EFIS altimeter setting
- Correct animations for mode / range
- Enable heading-track switch animation (incorrect object-name)
- Add previews