Add testing for Django 1.11 and Python 3.6

[jdufresne]

Fixes #289

[codecov-io]

Codecov Report

Merging #295 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #295   +/-   ##
=======================================
  Coverage   72.87%   72.87%           
=======================================
  Files          10       10           
  Lines        1379     1379           
=======================================
  Hits         1005     1005           
  Misses        374      374

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ab574fd...7189683. Read the comment docs.