FlightGear - Flight Simulator FGAddon

* Models/FBcockpit.xml: remove all instruments, leaving only the
components specific to the FB Mk VI variant.
* Models/cockpit.xml: merge all improvements from revision 1602
back into this file, including all new instruments and controls.
This file is common to both variants.
* Models/Mosquito-FB6.xml: use both FBcockpit.xml and cockpit.xml.
* Models/Mosquito-B16.xml:
- animate bomb bay doors.
- merge selected improvements from Mosquito-FB6.xml.
* mosquito-common.xml: add keyboard shortcut 'd' to toggle bomb
bay doors.
* Nasal/startup.nas: fix a typo.

* Make the FB Mk VI FDM common to both variants:
- mosquito-yasim.xml: delete.
- mosquitofb6-yasim.xml: rename to mosquito-yasim.xml.
- mosquito-set.xml, mosquito-fbVI-set.xml (sim/aero): delete.
- mosquito-common.xml (sim/aero): new.

* Delete unused duplicate files:
- Models/Instruments/oil-temp-gb/oil-temp-0.xml
- Models/Instruments/oil-temp-gb/oil-temp-1.xml
- Models/Instruments/oil-temp-gb/oil-temp-p.xml
- Models/Instruments/oil-temp-gb/oil-temp-s.xml
- Models/Instruments/starter-gb/starter-0.xml
- Models/Instruments/starter-gb/starter0.xml
- Models/Instruments/starter-gb/starter1.xml