Support for Polish

[langalex]

I tried adding Polish but couldn't figure out what to do so I wrote a separate gem. I'd prefer to merge it with this one if someone could explain to me how or point me to some documentation.

[dblock]

I think you should check out a PR for a new language, like this one for Estonian: https://github.com/kslazarev/numbers_and_words/pull/82/files. It's pretty much copy-paste for Polish from there.

[langalex]

thx, good idea. will give it a go.

[d4rky-pl]

@langalex can't wait for your pull request, I wanted to do the same thing for a long time :)

[langalex]

@d4rky-pl sorry to say this but i'll be on vacation for a few weeks so don't expect anything soon. feel free to take the gem i made and integrate it though :D

[dblock]

Unfinished in #189.