I added `C-M-0` for flip and `C-M-=` for rotate, so far liking it.

Oddly, I think '0' (or 'O') may make more sense for rotate? With '=' good for horizontal flip and '|' good for vertical flip? I'm probably trying to force more meaning in the character than makes sense. :(

I will say that these are immediately useful when any of the automatic splits picked the wrong "side" from what I wanted. Really really useful.