Add Soundex

I had not heard of soundex before. That would be an interesting project, but I think it's a separate module. The core search module would probably be a better model to work from because I think you'd only need to store each soundex translation once in the index, whereas a word in this module has multiple index entries.

It would make for a very interesting project, but I'm marking as won't fix. If you really need it, I could be hired to do it later this year. If so please contact me directly.

Thanks.