Display community profile

Contains:

* slug field moved right after name field for Community Model
* fixes with imports
* test class for testing views
* generic method for checking status code + unittest for display community profile view
* view and template to display community profile

The `dashboard/base.html` is contained in #27.
I'd use `get_object_or_404` explained [here](https://docs.djangoproject.com/en/dev/intro/tutorial03/#a-shortcut-get-object-or-404) rather than try/except with `raise Http404`.