Fix distance sensor telemetry reading

ADSB server support provided through new ADSBVehicleManager implemenation

Fix flight timer

Better flight trajectory point algorithm

Plugin'ized follow me support

Enable ArduPilot motor testing

Support up to 64 buttons, not limit to 16
Send a single button command and not a stream of commands at 25Hz
Send button commands through signals (it's coming from a different thread)
Hide gimbal support through analog channels (there are no MAVLink messages to handle it)

Map gimbal controls
Keep track of gimbal position within Vehicle

Add gimbal to external control signal

Instead of trying to keep a vehicle type within the FirmwarePlugin instance, pass the vehicle to the function so it can query the type that way.

Fix mavlink version negotiation for single vehicle

Add Throttle % as vehicle fact

Save/Restore stream rates. Auto flight mode support

PID tuning rate adjustment

Smart RTL support

ArduPilot: Flash bootloader support

Support STATUSTEXT_LONG

Remove the concept of reserved buttons for manual control

Add gotoFlightMode property

Show orbit telemetry status on map

Heading to Home on Vehicle FactGroup

Add Distance to GCS to Vehicle FactGroup

This reverts commit c69a49e6.

Move ArduPilot preflight check handling to generic QGC

Fixed the core MAVLink receiver. Among other things, it wasn't accounting for fragmented messages.
Fixed code that monitors messages received (and lost)
Added a section within the MAVLink panel to show the current status (for the current vehicle)
Remove some old, unused exposed interfaces

Also fixing some c++ errors within commented off code as the localization engine was getting confused by it.