Removed autogenerated files.
Comments, formatting, and changed the tokenizer.

I better documented regexparser.py (although I feel like it could use another editing pass, this should be good enough for now). I improved the formatting, mostly regexparser.py but a little regex.py. And I changed the tokenizer rules somewhat to make them hopefully a little simpler conceptually. Also some other slight changes.
Fix for bizarre bug.

For some reason my tweaks caused python to fail to reload the import with \+ as the regex (at least, as far as I can tell that's what's happening). Mysteriously, putting the regex in, even commented out, fixed the bug.
Added a shebang.

Also changed \r\n to \n throughout the file so that the shebang would actually work.
Improved the interface to class NFA.

It's not referentially transparent, but at least there aren't seemingly
unrelated functions that have to be called together for the code to work.
Also changed a comment.
I forgot to delete the function from earlier.

It's now worse-than-useless, so it's gone.
Added some documentation.

I'm wondering if the comments above the construct_foo functions are
really necessary. I suppose, though, that they're just obscure enough that
someone looking at them for the first time would benefit from a
brief description of what they're doing.
More code cleanup.

Removed some undesirable functions, made some functions "private". I'd
like to get rid of the DFA.reset function, Although I'm still undecided
as to the best way to do it.
Removed DFA.created

Now uses num instead. This is uglier, but removes a bit of mutable state
in the class.
Added command-line interface.

Added command-line interface as specified in the README. I also
reworked the README somewhat - although I'm still not satisfied
with it and I'll probably edit it again.