Update setup.py

As per mgilson suggestion on StackOverflow.
http://stackoverflow.com/questions/13361510/typeerror-unsupported-operand-types-for-dict-items-and-dict-items
http://stackoverflow.com/users/748858/mgilson
We adopted "An alternative way to add a pair of dictionaries which works on py2k and py3k".
Thank you mgilson.