Missing dependency info on PyPI

[jnohlgard]

The six module is missing when installing in a clean virtualenv (py34). I think the dependency info seem to be missing from the PyPI package.

(tmp) % pip install blitzdb
Collecting blitzdb
Installing collected packages: blitzdb
Successfully installed blitzdb-0.2.12
(tmp) % python
Python 3.4.3 (default, Jan  2 2016, 11:36:17) 
[GCC 5.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import blitzdb
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/jgn/.virtualenvs/tmp/lib/python3.4/site-packages/blitzdb/__init__.py", line 1, in <module>
    from .document import Document
  File "/home/jgn/.virtualenvs/tmp/lib/python3.4/site-packages/blitzdb/document.py", line 8, in <module>
    import six
ImportError: No module named 'six'
>>> 
(tmp) % pip install six
Collecting six
  Using cached six-1.10.0-py2.py3-none-any.whl
Installing collected packages: six
Successfully installed six-1.10.0
(tmp) % python         
Python 3.4.3 (default, Jan  2 2016, 11:36:17) 
[GCC 5.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import blitzdb
>>>