Dungeons no longer overwrite the dungeon border; the border now simply
overwrites the dungeon. This could cause problems, but it's better than the
other way around. I'll fix it someday. Also did some refactoring. Michael,
consider adding the following lines to your .vimrc:

autocmd ColorScheme * highlight ExtraWhitespace ctermbg=red guibg=red
highlight ExtraWhitespace ctermbg=red guibg=red
match ExtraWhitespace /\s\+$/