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 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.

Convert bool settings to SettingsFact

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

Fix knots to m/s conversion. Oops.

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

Scale increment and decimal fields according to cooked unit, so that the decimal and increments provided by meta data still work in the cooked display