Merge pull request #46 from ambitioninc/master

Updating master's fixes
added support for different pk fields and updated tests
added sync test for different pk
bumped version
bumped version and merged with develop
fixed python 3 support
Merge pull request #47 from wesleykendall/develop

Support for custom pk fields
Merge pull request #48 from ambitioninc/develop

Support for custom pk fields