Starting point for real implementation

- properties now hand off of main “autopilot” object in qml
- Added support for summary items through qml

This way you don’t need to know parameter set ahead of time.

Plus a large number of other changes to allow for orderly shutdown of
objects without crashes or asserts. This is need for unit tests to
create/delete global state around every test.

Allows parameter access from QML among other things

- allow unit tests to use QGCApplication
- clear global singletons for each unit test run