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

Used to display items associated with Flight Plan on Map

Fixed found bugs

Plus low battery announce changes