Update README.md

Added "A quick google query, "pen testing word lists", points to Pymangle (https://github.com/esheldon/pymangle).  Their google code page states "PyMangle is both a python command line tool and a python library used to create word lists for use with other penetration testing tools."  I haven't delved too deeply into Pymangles functionality but it might be a better option than writing my own program."