Use Python3 urllib if available
Use relative imports (PEP328)
Fixed unicode literals in migrations
Fixed unicode literals in edit handlers
Fixed a couple more absolute imports
Use Python3 StringIO and urllib, fallback to Python2 if not available
Use six to help with checking whether an object is a string
Fixed some more absolute imports
Use __str__ when converting Query objects to a string
Python 3 doesn't suport dict.iteritems()