Small tweaks to tokenizer's handling of comments.

I needed it to be able to understand a single hash sign as a comment
identifier as well, not just a double hash sign.
Added SWANTBLS support.

Boom's ANIMATED and SWITCHES lumps can be converted back to SWANTBLS
definitions; and SWANTBLS definitions can be compiled back into ANIMATED
and SWITCHES lumps. Note that decal information is lost when converting
to SWANTBLS.