slideshow, similar to Jordach's old TV mod, but using the game's animated
texture feature and a vertical strip of images instead of an ABM. Animation
time set for 80 seconds, so each of the 8 images shows for 10 seconds.
The textures were drawn to counteract this, without my realizing I was doing
just that. :-) Fixed. Also replaced all "tile_images" references with "tiles",
since the former is deprecated in favor of the latter.
