Drop Python 3.3 support

[ps-george]

• Dropping support for python 3.3 as discussed in Allow running tests programmatically #799
• Fixing test_web.py, wsgi has been superceded with pywsgi

[codecov]

Codecov Report

Merging #804 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #804   +/-   ##
=======================================
  Coverage   65.11%   65.11%           
=======================================
  Files          14       14           
  Lines        1422     1422           
  Branches      224      224           
=======================================
  Hits          926      926           
  Misses        444      444           
  Partials       52       52

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[cgoldberg]

before we merge this, could you remove mentions of Python 3.3 from the following files:

./docs/installation.rst
./README.md
./setup.py

thanks!

[cgoldberg]

lgtm

[cgoldberg]

👍
thanks!