Moving methods from MainWindow to QGCApplication so that more things
can run without a window. Helpful for testing.

Emitting signal beforehand can lead to subtle bugs where code expects
value to be updated and it is not.

Starting point for real implementation

No longer needed with move to summary page qml

Summary page is also the launching spot for the setup screens. No more
left hand set of buttons.

This prevents mavlink signals from being emitted after link is
disconnected

When using DeleteOnClose with a QQuickWidget, the shutdown sequence
causes the MainWindow destructor loop back onto itself.

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

UASWaypointManager: don't clear systemid and compid of last partner so that we can still get DO_JUMP updates

UASWaypointManager: accept single waypoint messages in order to update the remaining DO_JUMP repetitions

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.