- Look backwards from insert point
- Only pull altitude from _WAYPOINT items
- Only set altitude on _WAYPOINT items

* Holds all the settings for the app
* Allows core plugin to override default values

Also added ui support for multiple complex item types

Use component id from heartbeat

- Shot Interval in Survey
- Much change to time/distance calc

Conflicts:
	src/MissionManager/GeoFenceController.cc

Retry in all the right/possible places. Don’t freak out about things
coming in unknown sequences.

_finalize methods need information which is not available if all you
have is a mavlink_message_t