Mavlink terrain protocol support

Put back ToolStrip titles which were mysteriously removed

Are you sure check on preset delete

Support for built-in preset delete prevention

Handle gstreamer signals on main QGC thread to avoid deadlock; Remove video sink from pipeline if pipeline failed to start

Fix altitude mode setting for correct control display

Don't show (Rel) all the time

Fix load order so isManualCamera returns correct value

Show errors from preset load failures

Allow telemetry settings section to hide

Fix Done Tracing <-> Done PolyFoo in wizard relationship

Fix waypoint linkage to first item

Add missing hideDialog call

Remove close dialog from click handlers

added function to FlightView to show the checklist if switching views from a view other than FlightView and if checklist should be shown

Drive Plan view ROI support from firmware capability bits

Avoid arrow positioning with take item

Only check latest stable firmware one time

Cleanup download object on error

Fix typo

Track trace mode in polygon so we can use it to exit wizard mode

timer.start() and timer.stop() were breaking the 'running' binding of
the timer

Fix current item updating after delete

Not setting _isIncomplete correctly was causing crash

Fix Plan insert Takeoff/Land for correct enable state and insert into correct place. 

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Plan: Make PX4 VTOL takeoff work like fixed wing