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.

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

Initial Corridor Scan support

initial Jenkinsfile OSX build configuration

Use runtime discovery of cpu core count

Float comparison to flakey cross-platform

Fix leaking QNetworkReply

Write only metadata

Move  MAV_PARAM_TYPE to  MAV_PARAM_EXT_TYPE as we're now using the proper MAVLink version.

Add gstreamer debug log option, and dot file output

Localization update

Fix NMEA settings layout

Insert ROI command which is supported by firmware

Structure Scan: Structure height support

Hide popup icon until mouseover

Compute plan view items visibility on the fly.

Handle settings when armed

Remove disabled yawVehicleToStructure option