version_info broken in python 2.6

[catherinedevlin]

The README reports Python 2.6 compatibility, but the version_info checks rely on it having named component attributes, which wasn't true in 2.6

https://docs.python.org/2/library/sys.html

Changed in version 2.7: Added named component attributes

    if sys.version_info.major == 2:
E   AttributeError: 'tuple' object has no attribute 'major'