Properly handle distortion meshes when flip-Y used

[russell-taylor]

Emma noted: I noticed something weird when testing new meshes. Using the same config file, when I run RM demos vs Unity demos (Palace and Wendy), the meshes are flipped in the y-direction. I believe that the orientation in the RM demos should be correct - otherwise my tests to undistort would have showed this error - but I am verifying this by graphing the mesh data and playing with test configs.

This will presumably also happen with COP offsets in symmetric polynomial distortion correction. It might also happen with OpenGL/DX Interop.

[russell-taylor]

This may be fixed in #373
That will fixed COP issues with polynomial distortion but may not have fixed the issue with meshes.