wind direction correction angle

[pljakobs]

I can't reopen #43 so I will open a new issue

building off the most recent code, I noticed that you added a few ui elements to configure wind angle conversions in general, I feel that this might have a place to live somewhere. I understand that the directionality is still worth thinking about, but it would really help my case (and I guess others, too) to be able to configure a correction angle.
Maybe a "wind source" selector and with it a correction?

[wellenvogel]

As I already wrote on the other issue:
I agree on the idea behind - but at the end it's still a bit out of scope for the converter.
And if we would start on that it needs a more general solution (otherwise with every new wish the software needs to be adapted at several places - hard to maintain). Some simple offset operations are easy to be implemented - but the general concept is more complex.
At the end you still can create your own fork and add the computations that you need by your own as you could focus on your particular use case. It's open source :-).