[bug 937650][bug 937653] JSON Snippets models and views.
Upgrade to latest playdoh-lib and Django 1.5.5.

Upgrade django-smuggler to 0.4.1.

SECRET_KEY cannot be empty.

Return iterable when mocking filter().

ALLOWED_HOSTS must be set in production.

Default Template Foreign Key should be None for migration.

Add client to TestCase.

PEP-8 fixes.
Merge pull request #46 from glogiotatidis/upgrade-django

Upgrade django
Improve SnippetManager's tests.
[fix bug 946770] Add locale info to Snippets Stats Ping.
Add 'is_exclusion' in CMR list_display.
Add 'get_absolute_url' Snippet method.
Allow authenticated users to view disabled snippets.
Merge pull request #49 from glogiotatidis/exlusionlist

Small improvements
[fix bug 964677] Do not include 'target_geo' in json response if no country.
Merge pull request #50 from glogiotatidis/master

[fix bug 964677] Do not include 'target_geo' in json response if no country.
Fix bug 970894: Move snippet preview form outside of main form.

hoosteeno tracked down an issue with the snippet preview to the fact 
that it used a form within a form, which isn't allowed by the html5 spec
and apparently doesn't work in Nightly anymore. We fix it by moving the
preview form outside of the containing form.