Needed to support different indicators for advanced mode

Moved "Grid Lines" out of General Options and into the Video Stream Widget
Made a QGC custom Switch element

Nope, it's microseconds alright. The autopilot I was testing with indeed only had 19 seconds of "armed" time.

Also hand carried text to speech changes from Stable to master. Plus
unit tests for that.

Still does not support multi-vehicle

Fix merge issues

Switch only to MAVLink 2 on first connected link. Fall back to v1 if two links to the same vehicle are connected and one can only do v1

This extension introduces a complete version handshake mechanism which will detect wether the vehicle AND the complete link / routing infrastructure support MAVLink 2. If they do, QGC will switch to the highest protocol version supported by all connected vehicles. If a new vehicle connects, it will re-negotiate the highest possible version. This means that we error on the side of compatibility, which later can be easily changed.

Remove/comment off debug output pollution