FirmwarePlugin: Issue a warning upon connecting if the firmware in use is not using a stable release

Enable/Disable based on fixed base position

9 digit precision for lat/lon

Fix meters to mm conversions

Fix typo

Add support for specifying fixed RTK base position

Added support for qgcRebootRequired Fact meta data value.

Fix critical check

Add box around map warnings text

PX4 prearm checks severity

Change to case insensitive compare

Move ArduPilot preflight check handling to generic QGC

Fix mobile builds

Custom build override for stable version check no longer needed

Stable desktop version check

Multi-Vehicle Start/Pause Fixes

Prevent clicks going through top level items

Remove unused code

The X-UAV Mini Talon is a V-Tail plane. This commit adds the
new group "Plane V-Tail" together with a svg image for the
new group.

Fix terrain NaN making it all the way to Planned Home altitude.

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.

Limit all queries to areas smaller than 500km^2. If an area of interest is greater, clip to 500km^2 centered on current ROI's center.
Removed the identifier "Airmap" from error messages coming from Airmap.
Added a clipping function to QGCGeoBoundingCube (clip polygon to given area)