Fixes for Django 1.8.9

[tkwon]

In order to get this to work I had to do the following:

In response.py
Change

 from django.utils import simplejson as json 
 return HttpResponse(response_data, mimetype=mimetype)

to

import simplejson as json
return HttpResponse(response_data)

In embed.py

from django.utils import simplejson as json

to

import simplejson as json