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

* Deal with missing parameters on Solo

* Fix trigger set

- Cache only supported on PX4. Solo sends param updates at a high rate
to update gimbal values. This was causing the cache to update itself at
too high of a rate, killing performance, especially on iOS.
- Fixed read/write index usage to provide correct progress bar updates

They may show up after parameters ready is signaled. No way around this
since this is a protocol problem. So can’t test secondary component.

Also don’t pop errors for initial request failure on generic vehicle.

Doesn’t have a done key which doesn’t work with our user model. May
find a better fix later.

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

All qsTr calls done

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>

All facts are numeric, atm. this means that the input should only
accept numbers. it already had the     inputMethodHints:   Qt.ImhFormattedNumbersOnly
option, but for some reason it still accepted letters and symbols.
by adding a     validator: DoubleValidator {} we limit the characters
to numbers only - and if the value is a integer, it will still work.

Tested by adding waypoints on the map & messing with the GPS coordinates.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>