Mavlink terrain protocol support

Put back ToolStrip titles which were mysteriously removed

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

Makes more sense for it to be in VideoStreamer as it takes care of managing
the video streams.

Fix sizing/scrolling

Use parsebin for automatic stream demuxing and parsing; Automatically insert rtpjitterbuffer for RTP streams to avoid video stuttering

Switch to decodebin and use decoder with highest rank; Use GL context provided by qmlglsink; Fix JNI code for AndroidMedia initialization

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

Fix video initialization - VideoReceiver did not start because sink was not created because videoBackgroundComponent was not loaded on startup if video was disabled

Support Keep map centered on vehicle

Use consistent "Launch" naming

Remove Fly/Plan from toolstrips

Make Toolstrip flickable, fix maxHeight, fix bunch of margins

ADSB server support provided through new ADSBVehicleManager implemenation

A contextual Land/RTL tool. Better waypoint line calc.

Rework Mission Complete dialog for correct Resume Mission on ArduPilkot

Hide pre-arm message when vehicle arms

Fix bad merge