Update MAV 2 switching semantics

Link reference bug fix

New CenterMapDropButton control

Correct handling of no GeoFence support

MobileFileDialog bug fixes

Be a little less picky about level horizon

Correct UAVCAN settings

ArduPilot: Onboard compass cal support

LinkInterface/LinkConfiguration now reference counter using QSharedPointer

Even though it hasn't been supported forever, the files where still
being compiled

Prevent shutdown ordering crashes

PX4 doesn't retry commands by default

Change priority of messages from which altitude comes from

Also changed GPS FactGroup values to use NaN appropriately to show
unavailable values.

Don't show dynamic links in Comm Links

Turn off command retry logic for PX4 Stack

No need to add dynamic MockLink comm links

Change airplane compass icon to generic arrow icon

Null pointer issue

the message handleAltitude