Support for character sprites

[baconwaifu]

It's trivial to support character sprites as well: just change the filter in the download_spinelobbies code to look for spinecharacters instead. Note that for some reason while the lobby spritesheets are normal, the character spritesheets are vertically mirrored, so need to be corrected (such as via convert -flip) before they'll display correctly. Aside from that the viewer works perfectly with them without any additional modifications (although it does really like "fill" to mean "zoom in so there's no borders at all, even if it means most of the sprite goes off screen" when displaying a portrait on a landscape screen...)

[respectZ]

Alright noted. I don't have much free time to commit on this one atm, so don't expect it soon.