Python 3.3+ support, added six to requirements, bumped requests version,...

Added Six to requirements (This library help with making things work both on 2 and 3)
Made enhancements to work on both Python 2 and 3
Requirement change Requests >= 2.1.0
Remove lxml requirement, replaced with standard library xml
PEP8 cleanup
Tested with Python 2.7.6 and 3.3.4