LMU2PNG: Panorama background is scaled improperly

[jsp4cter]

The parallax background on generated images is erroneously scaled instead of tiled. This bug was not present in the older, commandline-only version.

320x240 map with 640x480 panorama

Old version behavior, properly cropped

New version behavior, scaled downwards to fit

This issue is particularly egregious on larger maps.

If this functionality is intentional, I suggest making it toggleable.

[carstene1ns]

Yeah, needs to be toggleable.
The reason I introduced is that in other cases it looks bad when tiling. (e.g. a big sky gradient panorama that was only intend to tile horizontally will show the bright part at bottom again).

At that time I was not sure what other options make sense, scale horizontally/tile vertically checkbox or a select field.
For the cli this would IMO need 2 new options.