Use the transform definitions from Wayland by the letter

It seems Weston got the monitor vs. content rotation the wrong way, essentially leading to 90 and 270 transforms being swapped. Swap them to follow the letter of the Wayland specification.

The swap is split into multiple patches by component. While it doesn't cause any issues with normal orientation, one could argue that there are temporary regressions between the patches, e.g. weston-transformed working "wrong" on Weston for a while. But I think it is easier to review split like this. They can easily be squashed too.

As a result, if you have 90, 270, flipped-90 or flipped-270 in your weston.ini, you have to do the 90/270 swap too to keep your orientation.

I chose not to change the weston.ini value to transform value mapping to keep it simpler. Particularly #52 (closed) could suffer complexity otherwise.

Fixes: #99 (closed)