More work on mission item indicators

Use new SplitIndicator control

Allow split of current segment

Hide waypoint indicators unless they are really needed

Add Terrain toggle to MapScale control

More work on direction arrows

Zoom buttons move to MapScale control

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)

Fix : COGAngle indicator was shown everytime, fix isCOGAngleOK

- NorthUp becomes NoseUp and is disable by default
- Changes on SVG to make them with the same diameter as the CompassDiag
- Change the order of the indicator layouts

- Remove HomeHeading / COG / HeadingToNext
- Add setting AdditionalIndicatorsCompass that group the previous
  settings

- Add setting for Heading to Next WP and Nort Up lock
- Add check for vehicle for every indicator to avoid showig them while
  no vehicle

- Reimplement same behaviour as version 3.1 while resizing the window :
    Stretch the text area to fit the screen
- Change setting text from Alternate Instrument Panel to Vertical Instrument Panel

- Rename QGCInstrumentWidgetAlternate to QGCInstrumentWidget as it's now the default version
- Select  QGCInstrumentWidget as instrumentLoader source

The instrument widget layout is now a stack of :
- QGCAttitudeWidget
- Item that contain ValuesWidget
- QGCCompassWidget

Fixed flight widget position.

Get rid of QGCView, QGCViewPanel and FactPanel. All messages and dialogs are now handled in the root window.