Updated to work with Django 1.11/2 + python 2/3

[chanceraine]

Warning - this is a major revision
Things fixed:

• Relational field population now works properly
• Constraints (unique/unique together) are now taken into consideration
• Added a lot more tests (https://travis-ci.org/chanceraine/django-faker)
• Works with more standard versions of Django now (1.11/2)

Personal, More Controversial Improvements

• Snake case'd everything
• Refactored how populator does its guessing a bit
• Broke backwards compatibility left and right

[coveralls]

Coverage remained the same at ?% when pulling a8934a4 on chanceraine:master into 345e3ee on joke2k:master.

[coveralls]

Coverage remained the same at ?% when pulling a8934a4 on chanceraine:master into 345e3ee on joke2k:master.

[rosscdh]

+1