added: VORs to airport detail view and map view. Tap to send frequency.

added: ability to toggle display of land airports, heli ports and VORs

added: PDF Airport Charts (requires internet connection)

changed: mapview will now auto-rotate into portrait mode

added: option to disable auto-locking while the app is running

added: simultaneous live tracking of up to 7 X-Plane AI aircraft

fixed: crash when aircraft icon was tapped

fixed: map view zoom level when no default was set

fixed: memory leak that caused a low mem warning/crash in live tracking