Fix Plan save message on exit

Replacing colors with the ones provided by Airmap.
Adding border color and width.
Adding airspace ID so it can later be linked to the advisory list.

Added some basic color management for airspaces

Handle flight start/end time
Handle start/stop traffic monitor
Only start telemetry if enabled
Added a "Now" button for the flight start time
Collect advisories only when the rules change

Updates in general was only done if a POI changed. This caused changes related to something other than a change in POI to be ignore. The code now "resets" the POI when such changes occur (change of ruleset for example).
Ruleset selection is was not persistent. When reloading the list of rulesets for a given region, any previously selected ruleset would be reset to defaults.
Also fixed several new clang warnings.

* Load Plan
* Save to KML
* Load Plan (it tries to load KML instead)

Create new, specific button for clearing mission from vehicle
Adjust sizing of DropPanel

Have different modes for the Airspace Widget (Plan/Fly)

Adding missing qgcView to QGCMapPolygonVisuals instance in SurveyMapVisual.qml

Make all argument to AirMap queries based on what the screen shows (bounding rectangle and/or radius), respecting the limits imposed by AirMap.

AirspaceManager is now exposed by QGroundControlQmlGlobal instead of Vehicle (available all the time)

Fix sorting issues with QmlObjectListModel
Show airspaces in Plan View as well

Added an "unavailable" icon for when no vehicle is connected
Toggle restriction overlays (map) on/off based on the airspace widget being expanded/collapsed respectively

Handled "airspace visible" state (not done)
Adjusted restriction map items color and opacity
Added/Updated icons for airspace traffic
Adjust colors for text over maps

All settings wired and persistent
Cleanup non Airmap builds

Eliminated flight widget "states"
Define flight widget top margin (plugin options)

Adjust colors
Remove unused image