FlightGear - Flight Simulator FGAddon

QSeries: add file I forgot in previous commit, small adjustments

QSeries: restore accidentally removed checklists file, move to gui/dialogs/

QSeries: major overhaul, including amazing textures by C-THAL, re-organized instruments

DA40NG: Restructure, add source files, add basic passenger over multiplay

PA28: Correct mistake in FCS

Add some 'eye-fixed' tags to a few aircraft to fix 'Drop view' with the current view system.

(Patch from Julian Smith.)

De Havilland DHC 1 'Chipmunk' : Some modifications on the instruments and flaps. Thanks to HerbertP

branching for release 2020.3

CRJ700-family - major update from Henning STAHLKE

Dragonfly:
FDM:
- Adjust some derivatives (Improved side slip)
- Adjust thruster and engine location (was too far aft)
FCS:
- switch sign of aileron control to be more consistent (Right flap down is positiv)
Set-File:
- Set Status
Banner:
- Remove workaround
GUI:
- Make sliders live in weight_and_balance