UAV Outback challenge improvements from Team Swiss Fang

This is the collection of improvements done by the swiss team at the outback challenge. Needs validation / polishing.

@thomasgubler A merge with master would be great, I got confused by the (only two!) conflicts.
10 was for the radio data link, but yes, we could go for e.g. 4 and see how we do. The additional RAM however is a close call on FMUv1, so anything larger than 2 needs testing on it (in particular when connecting USB).