There are times when it would be very handy to be able to rotate the
view of a PCB layout or schematic. I don't mean by changing the layout
or schematic itself, but rotate how the layout or schematic is VIEWED.
It'd also be handy to be able to flip a PCB over so you're viewing it
from the bottom, rather than the top.
This is nothing more than coordinate translation when drawing the screen
and interpreting click locations. It wouldn't change anything stored in
the schematic or board file, so the effects in the code should be
relatively localized.