Fix TCP disconnection problem.

Still does not support multi-vehicle

Fix merge issues

This reverts commit 52160d80.

This is important to avoid having QGC hijack links that are active (we read 2000 bytes!) but are definitely not MAVLink. This can have nasty side-effects, e.g. if we would talk to an LTE modem in a laptop or alike.

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

Pulling mavlink with a reversal for the CAMERA_IMAGE_CAPTURED message. It's now back as it was so it won't break existing code.
The pull also brought changes to the GPS_RAW_INT message. Only MockLink uses. I entered zeros for all new fields.

PID 0xea60 = 60000 , not 600000 (which is well beyond any valid PID)