Aspect ratio for 256x239 mode

[kingpost]

I noticed that the core uses the same aspect ratio (64:49) for games in 256x224 mode as well as 256x239. While I agree this is the correct AR for 256x224, it is not for 256x239.

To calculate the correct AR: active resolution (256x239) * exact PAR from pineight.com (8:7) = 2048:1673. (There is no GCD for this result other than 1, so 2048:1673 can't be simplified with smaller numbers.)

So, when "Aspect ratio: Original" is selected, if the core could automatically switch between a 64:49 AR for 256x224, and 2048:1673 for 256x239, it should be perfect.

(I acknowledge this is a corner case because not many games run in 256x239. However, I thought I would go ahead and raise the issue while I was thinking about it.)