Add Rosetta - Python text processing library

Rosetta is a Python library to make data-science on textual data easier.
The library contains a number of high-performance utilities for common tasks
encountered during text-mining (e.g. tokenization).
The library also contains a number of wrappers to make working with libraries
such as Vowpal Wabbit and Gensim simpler.

Introductory video: http://youtu.be/Xv6exLVbGPk