Fixed all deprecation warnings as of Django 1.5

* Now uses native json module rather than simplejson where supported
* No longer uses django.conf.urls.defaults on newer versions of Django
* Uses native copy module rather than Django's deprecated copycompat if the python version is >= 2.5.  This was the release that the native copy module started to support copying functions.
* Now using request.body instead of the deprecated request.raw_post_data.