Made QGCCorePlugin derive from QGCToolBox and expose everything through the same mechanism as everything else.

The return lead to data being dropped. Some of this data could have been
part of the ulog header, which lead to corrupt files.

Moving source files into Vehicles as it is a more coherent place.

Forcing QGC to use Mavlink V2 if vehicle supports it.

Also added new FirmwarePlugin::brandImage support

_finalize methods need information which is not available if all you
have is a mavlink_message_t

Includes ability to load params

- GeoFence support comes from plugin
- Circle fence support
- Better param support

Move battery.percentRemainingAnnounce to Qml Global

The static Fact was causes problems with Qml