- select active vehicle
- arm/disarm
- select flight mode

- New MissionManager
- Plumb MissionManager through MissionEditor
- Mission Editor supports get/set

- MultiVehicleManager is a Qml friendly replacement for UASManager
- Vehicle is a replacement for both UAS and AutoPilotPlugin

- FirmwarePlugin is the new place for code which is specific to
firmware flight stack
- FirmwarePlugin currently supports flight mode apis
- Modify code to use new FirmwarePlugin support

Increase timeout for param apply, make app wait run in a shorter loop to avoid having the OS concluding things do not work.

Airframe QML: Fix order-dependency of config. Highlight selected airframe more clearly. Allow combo box action to select the airframe as well. Allow single click on icon to select airframe.