Add django >= 1.10 as a requirement.

[stylesen]

The lack of this creates dependency problem as provided by setup.py.

See the following Debian bugs:

• https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=896337
• https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=896205

[stylesen]

A new release with this patchset will be required to update this in Debian.