Unit test for mission transfer error string checking

Mavlink terrain protocol support

64 bit fixes

qobject_cast is times faster dynamic_cast for objects that
inherit QObject. also, use auto keyword to not duplicate
class names.

Map gimbal controls
Keep track of gimbal position within Vehicle

Use offline editing params for MockLink

Add support for ArduRover MockLink

Support STATUSTEXT_LONG

16 RC channels

Support parameters from multiple components

* Flight modes still not implemented. Waiting on message change.
* Also includes various cauterization of UI things which should not be
available on high latency link.

Fix merge issues

This reverts commit 52160d80.

Pulling mavlink with a reversal for the CAMERA_IMAGE_CAPTURED message. It's now back as it was so it won't break existing code.
The pull also brought changes to the GPS_RAW_INT message. Only MockLink uses. I entered zeros for all new fields.

Prevent shutdown ordering crashes