Added support for qgcRebootRequired Fact meta data value.

It was broken when temperature translation was added in babbfbd1
The system wasn't quite setup to handle anything other than speed and distance. Changed so any arbitrary unit type can be converted to another.

It was broken when temperature translation was added in babbfbd1
The system wasn't quite setup to handle anything other than speed and distance. Changed so any arbitrary unit type can be converted to another.

Move  MAV_PARAM_TYPE to  MAV_PARAM_EXT_TYPE as we're now using the proper MAVLink version.

It did not like the use of the tr() macro within a static QString in the constructor.

Ignore Fact index if there are no enums (avoid adding an "Unknown" entry)
Add function to convert and clamp a (Fact) value.

Removed guess work from what parameters must be refreshed/updated when some other parameter changes. Added a "reset" flag that indicates when a certain parameter changes, the list must be reloaded.
Don't send a signal when setting a fact if the new value is the same.

Increase param ack timeout.
Retry when param set failed.

Convert bool settings to SettingsFact

more conversion stuff

some fixes and added area unit drop down

Conflicts:
	src/MissionEditor/MissionItemStatus.qml

removed comment

finish unit conversion

correcting typos

Use constant's inverse to ensure we don't accumulate error when converting back and forth

Use constant's inverse to ensure we don't accumulate error when converting back and forth

 - Request list of all parameters, expecting device to lead each component with _HASH_CHECK cache value
 - Test for hash collision, if so our cache is valid and respond with _HASH_CHECK to stop listing
 - Else: let listing continue as normal to get updated param values
 - Store each cache by systemID + componentID

For #2586

Plumb through initial object mode on Vehicle