Fix showPanel calls

Prevent view switching apis support a stack

Add view switch prevention

Enable ArduPilot motor testing

* Flight modes still not implemented. Waiting on message change.
* Also includes various cauterization of UI things which should not be
available on high latency link.

This will make setup pages respond accordingly to armed state
transitions. This will also allow the settings on a page to at least be
visible while they are disabled.

Instead of hardcoded "QGroundContorl" strings

This makes VehicleComponents reusable from core plugin without
requiring override of prerequisiteSetup

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

Android done.