Update json.dumps calls to include DjangoJSONEncoder
Update json.dumps calls to include DjangoJSONEncoder

This fixes the problem where datetime objects can not be serialized.
More can be seen in the following SO question.
http://stackoverflow.com/questions/5583401/

crcollins/chemtools-webapp,crcollins/chemtools-webapp,crcollins/chemtools-webapp,crcollins/chemtools-webapp,crcollins/chemtools-webapp