FlightGear - Flight Simulator FGAddon

PBY-Catalina: allow the user to ignire fires with Ctrl+Shift+Click.

* Inputs/sys_controls.nas: delete; it did nothing.
* Catalina-set.xml (nasal/init): ditto.
* Help/Catalina-help.xml: rewrite and reformat help.
Adjust key bindings to match those in the -set.xml.
* Systems/terrain.nas (terrain_survol): change from a settimer loop to maketimer.
(start_wildfire, wildfire_listener): new, adapted from
/usr/share/games/flightgear/Nasal/wildfire.nas.

Note: in 2019.1.1, wildfires are invisible; this is a known bug in fgfs and
not aircraft-side.

Bombardier-415: bug fix: add type information to view parameters; allows Model View to work again.

Harrier-GR3: Use 'C' to toggle canopy; 'c' now defaults to toggle cockpit view.

This restores default behaviour for 'c' in fgdata. Also updated help text for
'c' and 'C' accordingly.

Nasal/autohover.nas: update our window fonts if user changes gui style.

Harrier-GR3/Nasal/HUD.nas: don't show HUD if multiplayer view.

Harrier-GR3/Nasal/autohover.nas: fixed bug when heading target is close to zero degrees.

Harrier-GR3/Nasal/autohover.nas: fixed issue when switching to vertical speed.

Need to reset target speed to 0, otherwise we used previous target speed.

Nasal/autohover.nas: protect against nil.

Harrier-GR3: Harrier-GR3-set.xml: made help text more concise.

Harrier-GR3: Nasal/Canopy.nas: improved toggle behaviour.

Used to have to wait until canopy was fully open before it would close.