Use builtin json instead of django.utils.simplejson deprecated in 1.5

For further explanation: https://docs.djangoproject.com/en/1.5/releases/1.5/#system-version-of-simplejson-no-longer-used
django.conf.urls.defaults is deprecated
Merge pull request #109 from zalmoxis/master

updated google versions up to 1.8.3
Merge pull request #110 from williambr/master

 Use builtin json instead of django.utils.simplejson deprecated in 1.5
Do version-dependent imports
Bump version 0.5.6
Mark dojango as 0.5.7 alpha