note for python 2.7 requirement, move to 3

[skorasaurus]

hey @eamonjohnson
A new brigade member and I were trying to fork this and ran into an error while installing the pip packages on python 3.5 virtualenv.

The installation of the packages worked fine when I made a new virtualenv in 2.7.

I can make a note of that in the readme, and move to 3.

[eamonjohnson]

Confirmed, pdfminer package is 2.7 only. Alternatives for 3.x: pdfminer.six, pdfminer3k.

[skorasaurus]

Guide for moving - https://docs.python.org/3/howto/pyporting.html

[skorasaurus]

http://python-future.org/compatible_idioms.html#strings-and-bytes

https://docs.python.org/3/howto/pyporting.html#text-versus-binary-data

[skorasaurus]

took a quick stab on my lunch hour for converting this and
realize that we'd probably run into issues..

ran `futurize --stage1 -w drocer-webapp/*.py
and futurize --stage2 -w /.py

replaced pdfminer with pdfminer.six (BUT you don't need to change name of package); https://github.com/skorasaurus/drocer-webapp/tree/python3

http://python-future.org/what_else.html?highlight=byte

but then I ran ; yes, 3 handles bytes differently than 2.