Minimal modification on syntax to be supported by Python 3.

Origininal Repo: https://github.com/aneesha/RAKE

A Python implementation of the Rapid Automatic Keyword Extraction (RAKE) algorithm as described in: Rose, S., Engel, D., Cramer, N., & Cowley, W. (2010). Automatic Keyword Extraction from Individual Documents. In M. W. Berry & J. Kogan (Eds.), Text Mining: Theory and Applications: John Wiley & Sons.

The source code is released under the MIT License.