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

Fix missing TTS stuff

Fixes for TTS on Linux

Stable merge

When downloading mission items from the autopilot we need to retry more
agressively, so use a shorter timeout. If we don't do this, we might not
re-request a mission item in time and the autopilot has already given up
the overall mission transfer.

This fixes the case where a mission request from QGC to autopilot or a
mission item from autopilot to QGC gets lost on the link and needs to be
requested again.

Batch terrain requests

Support batching terrain requests

Take focus to close editing

Add support for HIGH_LATENCY2

Fix unit translators

* 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.

By adding a member variable for the total mission item count, we can
actually correctly estimate the progress.

It was broken when temperature translation was added in babbfbd1
The system wasn't quite setup to handle anything other than speed and distance. Changed so any arbitrary unit type can be converted to another.

It was broken when temperature translation was added in babbfbd1
The system wasn't quite setup to handle anything other than speed and distance. Changed so any arbitrary unit type can be converted to another.

Initial Corridor Scan support

initial Jenkinsfile OSX build configuration

Use runtime discovery of cpu core count

Float comparison to flakey cross-platform