Merge pull request #4 from glogiotatidis/master

Update django-browserid.
Merge pull request #5 from glogiotatidis/master

Update elasticutils.
Merge pull request #6 from glogiotatidis/master

Update pystatsd to v1.0.0
[bug 810989] Update django_browserid.
Update celery and djcelery.
Delete celery and djcelery
[fix bug 847957] Upgrade django-browserid.