FlightGear - Flight Simulator FGAddon

an24b: bug fix: recreate fcs/throttle-pos-norm[0..1]

These properties were deleted in r4386 but this causes fgfs 2019.1.1
to crash on startup with the message:

FGPropertyManager::GetNode() No node found for fcs/throttle-pos-norm

In file /home/lbrenta/.fgfs/Aircraft/an24b/Engines/ai24.xml: line 49

Thread 1 "fgfs" received signal SIGSEGV, Segmentation fault.

There may be a better fix for this bug.

Ka6: adjust wingflex

PA28: correct (probable) typo

an24b (Engines/ai24.xml/psfc): adjust with references. Fix a typo.

B-25 (Systems/b25-base.xml/aircraft-version): update; had been incorrectly downgraded in revsion 4258.

C-160-Transall (Models/light/light-cone.xml): do not pollute the property trees of remote aircraft over multiplayer.

CitationX: minor fixes.
* CitationX-set.xml: correct the default and max weight of passengers, with reference.
* CitationX.xml (cruise): adjust the maximum weight.
* Models/Instruments/PFD/PFD3d.xml: correct a typo.

dhc6 (dhc6F-set.xml): amphibious, not just seaplane, as it also has wheels.

eurofighter (Models/Instruments/mfd-buttons.ac): bug fix: use the *.png texture instead of missing *.rgb.

Northrop-P61 (System/views.xml): minor bug fix: delete spaces surrounding integer values.