Lightning protection / grounding

I did a longer mental note on lightning issues which can occur with your groundstation.

As a result I think I will implement an diode rectifier and some capacitors so that you can directly connect an isolated transformator in the next revision. Opinions on that?

Hey, it is very intersting article!
We had not thought about it, we are searching it and check this pull request.

Yes that is my commit. I have actually abandoned the idea of the isolated transformator and suggest to use overvoltage devices combined with proper lightning rods.