FlightGear - Flight Simulator FGAddon

* Models/Instruments/Gascontrol/MiG-15bis-Gascontrol.xml,
Models/Instruments/Gearindicator/MiG-15bis-Gearindicator.xml,
Models/Instruments/Headsight/MiG-15bis-Headsight.xml:
replace calls to MIG15BIS.switchswap() with property-toggle, property-interpolate
and MIG15BIS.clicksound().
* MiG-15bis.nas (switchmove, timedswitchmove, switchinit, switchswap, switchback,
switchfeedback, smartinterpolation): delete.
(stop_gearindicator, gearindicator, init_gearindicator): delete.
(init_altimeter, init_altlamp, init_flapslamp): delete.

333 more lines of Nasal deleted :)