Support for new TakeoffMissionItem and Takeoff Tool 

Wizard Mode for Create Plan

Don't query terrain if no location

Don't query intermediate state

Fix failure handling

* 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.

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Plus many load/save fixes

Plus new unit tests