Band-aid fix for bulleted list rendering (#1803)
More complete fix for #1803

When a list is prefixed by more than one non-list line, output those
prefix lines as part of the same paragraph, not as separate ones.

Treat other lines not beginning with a "*" as continuations of the
previous list item.
Merge pull request #1820 from kxz/dtext-lists

Fixes for bulleted list rendering (#1803)
Merge branch 'master' into omnibooru