BUG: Add dev requirement for issue 50.

[binarysubstrate]

Fixes #50

[coveralls]

Coverage decreased (-0.3%) to 89.691% when pulling 280aa0a on binarysubstrate:issue_50 into 6ffc60e on JBKahn:master.

[coveralls]

Coverage decreased (-0.3%) to 89.691% when pulling 280aa0a on binarysubstrate:issue_50 into 6ffc60e on JBKahn:master.

[coveralls]

Coverage decreased (-0.3%) to 89.691% when pulling 280aa0a on binarysubstrate:issue_50 into 6ffc60e on JBKahn:master.

[coveralls]

Coverage decreased (-0.3%) to 89.691% when pulling 280aa0a on binarysubstrate:issue_50 into 6ffc60e on JBKahn:master.

[coveralls]

Coverage decreased (-0.3%) to 89.691% when pulling 280aa0a on binarysubstrate:issue_50 into 6ffc60e on JBKahn:master.

[JBKahn]

LGTM, the error is because of the Django 1.0.3 bug as referenced in the #48 which was patched in Django 1.10.4 (unreleased)

[JBKahn]

Thanks for the PR :)