Add message asking user confirmation to end a flight

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

An rather unfruitful attempt at consolidating Advisories and Airspaces (they are both arrays of Airspaces). No such luck as they vary wildly. In the end, I'm now exposing the restrictions (Polygons) directly (and inherently) instead of copying them.
Tweaked polygon overlay colors and borders.

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

Break apart string of classes into their own files as all in one file became unwieldy
Expose Airspace data in a QML ready format
Split global Airspace from AirMap (Only now I figured out the reason for the pure virtual root classes)
Refactored a bunch of things to make it consistent and/or obvious