Relayer feature request

Hi Andy and all,

I wanted to request a feature in the Relayer app, if it's not too much
trouble - the ability to map the generator and period to whatever
direction you want would be useful.

For example, I was trying to mess around with 20-tet Blackwood, and I
was hoping I could get the period mapped to the left-right direction
and the generator mapped to the upright-downleft direction. I
eventually found that the 8:9 layout worked for this, but only in
20-TET. Would it be a lot of trouble to add a feature like this?

Thanks,
Mike