FlightGear - Flight Simulator FGAddon

an24b: fix a typo introduced in r4809 preventing the transponder from working.

an24b: bug fix: make ARK-11 (ADF) instruments work again. Fixes #2223.

Harrier-GR3: Adjust HUD params so pitch ladder 0 deg line stays horizontal.

Behaviour of pitch ladder 0 deg line is controlled by <compression-factor>
which appears to need to be 11.0 in order to keep 0 deg line horizontal
regardless of aircraft pitch. Would be nice to derive an exact value.

Also tweak ladder width and height to be symmetrical.

777: Add Exterior Inspection checklists; make chocks size more realistic

Cessna337: add a pilot, visible only in external views

Patch by "Red Griffin": thanks!

777: Add walker, improve handy viewer; revision 20 of https://sourceforge.net/p/flightgear-777/777

DR400-Ecoflyer: remove dependency on DR400-jsbSim

Cessna337: bug fix: the outside of the model was too dark

* Models/Cessna337.xml: use the opaque shader instead of the bump shader.
* Models/Effects/Cessna337-uber-opaque.eff: override the combined
effect shader instead of the default shader.

Patch by Marvin Sinister; thanks!

747-400: add more aerodynamic data

777: hide OH panel and pedestal when in exterior view, hide exterior model when in interior view, correct external/internal views by Sidi762; add low poly pedestal by Lars0817; revision 19 of https://sourceforge.net/p/flightgear-777/777/HEAD/tree/777/