Refactor/fixes for ProximityRadar and friends

Clean up references to MainRootWindow globals

- add NOTIFY for distanceSensor property
- add DistanceSensorReadingsChange() callback prototype

- revert excessive NOTIFY
- adding MaxSensor into DistanceSensor frame handling

- add proximity radar view in map view
- add proximity radar view in video view

change distance label positioning in video view

clean up unwanted comments

- space up proximity sectors
- revert unwanted changes in qgroundcontrol.qrc

squashed commits

Move GuidedActionsController references to global

More work on encapsulation in Fly View

Major rework to support terrain profile display and terrain collision reporting

Propagate opacity and interactive properties to mission items
Set opacity to 0.5 for items that are not part of the current
edit view

Stable update

Use global palette

Bring back visual sequence number in map item indicators

When a child item is current show the parent as selected

Active ROI indication in Plan Map items

Remove unused code

ADSB server support provided through new ADSBVehicleManager implemenation

Fix center drag and split side

Support for new TakeoffMissionItem and Takeoff Tool 

Better handling of invalid coordinates

More work on mission item indicators

Use new SplitIndicator control

Allow split of current segment

Hide waypoint indicators unless they are really needed

More work on direction arrows

Toggle Rally Point insertion on/off.
Highlight current Rally Point and current Waypoint.
Use tab bar instead of a row of radio buttons for selection (Mission, Fence, Rally).
Fix QGCHoverButton to handle proper checked state toggle.
Get rid of the many arrays used to define behaviors for the ToolStrip. They are now all defined within its model.
Fixed color for disabled text within ToolStrip (it was invisible)

Fixed flight widget position.

Adding missing qgcView to QGCMapPolygonVisuals instance in SurveyMapVisual.qml

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

Also rename QmlPageInfo to QmlComponentInfo to cover more use cases