Plus various bug fixes from flight testing

Corridor Scan: Support for images in turnaround

Fix multiple selected state for offline maps buttons.

More work on better unit tests

And fixes they found

Complex item unit test work

Clickable deadzone

Minor improvement to detection of stick recentering after calibration. Without this if you performed a calibration with deadband enabled but one of the deadbands at the end of the calibration was ~0 it would be very difficult to position the stick so that Qgroundcontrol considered the axis to be centered.

recentered after calibration.

Made it so that raw axis monitor indicators are narrow so that they don't obscure view of the deadzones.

New TransectStyleComplexItem base class

Allow loc of radios string

Support HIGH_LATENCY2.failure_flags

Robustify mission upload/download

More work in high latency

Update PX4 Firmware metadata Thu Feb  1 04:37:26 UTC 2018

* Command ack timeout back on normal/high latency link
* Correctly update ack timeout and high latency bit at correct times

Stable merge

Bad resume mission slider