Add unit test and shorten the core code. 

Hi,

I had a closer look at the code and implemented some unit test and refactored a bit the main code so that i can add more transformation in the future. Probably I will create new package as it would need a new name if it should support more encodings (Base64, BinHex, Sha1 etc). I like dangelov/hasher  plugin for sublime as it serves most of my encoding needs, so I'm thinking about implementing something similar.

Anyway here is the code just before I rename the package and add more encodings you may find useful.
Btw. You are welcome to contribute to the new package.

Cheers,
Piotr