Incorrect shapes in some cases when uprezzing HDMA

[LivelyZephyrs]

Another issue. This has to do with some shapes becoming deformed when being uprezzed.
Super Mario Kart (5x scale):

1x scale, how it's supposed to look:

Super Mario RPG (5x scale):

1x scale, how it's supposed to look:

[DerKoun]

The averaging of the windowing coordinates is too naive ATM.
The (too) simple solution would be to add a (fixed or configurable) threshold to define coordinates jumping more than n pixels being a horizontal edge.
But I'd prefer something a little more complex, analyzing one more line up and down, so diagonal edges that are close to horizontal can still be processed to HD normally.
I'll see if I can fit in at least the simple improvement in one of the next releases.

[DerKoun]

The simple improvement is now implemented: When any of the 4 window coordinates changes by more than 4 from one line to the next, no averaging is done across those lines.
For further improvements each coordinate should be handled separately and the threshold should be replaced by more complex detection. This is a low-priority to-do for the moment.