The logic for finding a region's cover image isn't always reliable

[rsvensson]

Summary
Occasionally when fetchinfo.py's getMobyRelease() function attempts to find the cover for certain regions, it can't seem to find the right cover and instead selects another one. This seems to mostly affect PAL releases.

For example, when searching for the PAL cover of Donkey Kong Country 3: Dixie Kong's Double Trouble! it instead comes back with the Japanese cover, even though there are several PAL covers to choose from.

Other examples are sometimes selecting a non-English PAL cover when there is one available (such as here), and sometimes the wrong English PAL cover (such as here where it chooses the slip-case release instead of the normal UK release)

Expected result
Well the logic for finding the cover is quite messy and needs cleanup, so it's not unexpected that it has issues. Still, it should ultimately behave as intended and only fall back to the wrong image if no other suitable image is found.