Add Terrain toggle to MapScale control

Zoom buttons move to MapScale control

Restore QGC to its normal UI layout (buttons on toolbar)

Offline Maps: Allow custom build settings overrides

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

Wrap text

* Export should always be enabled since you can export default tile set
* Fix Select All/None problem

Create a "Dead Mouse Area" control to eat mouse events underneath desired area. This is to prevent mouse events from leaking through controls underneath the area.
Replace original "NoMouseThroughRectangle" as this is more versatile.
Prevent mouse through events from leaking underneath the Fly View tool strip.

For whatever reason, showing the dialog through a function causes a crash in QML (undebugable--new word!)

Internet available now has a signal

This way:
* GCS location is shown
* It follows same centering semantics of FlightMap
* Note: Vehicle is not shown

Experimenting with Esri

Added top/bottom alignment state to map scale
Allow disabling instrument widget altogether
Added an otherwise redundant row to PlanToolbar so it matches the same button position as the main toolbar
Fixed typo (Math.max()) in ScreenTools
Fixed Javascript Exception in OfflineMap
Increased the import window size in OfflineMap
Added function to MainWindow to disable toolbar for a truly modal dialog
Added code so clicking on an open toolbar indicator will cause it to close