Update to Django 1.7.
Update test data.
Replace South migrations with Django migrations; remove south.
upgrade: Transition to native migrations.
Backup format version 2.

No longer relies on Django serializers and inspection
of migration history, in favor of a simple sql dump.
Add feature flags to show/hide accounts and flow sensing features.

This allows us to hide more complex features in the frontend
on systems which are not using them.
kegadmin: Rework the keg room.
kegadmin: add option to immediately tap a new keg.
core: Make keg description a text field.
core: Rename `tap.description` to `tap.notes`.

This private field is never rendered anywhere.
core: clean up keg lifecycle.

`keg.finished` and `keg.online` rolled into new `keg.status`
enum column.
Update test fixtures.
backup: use a raw query to get title.
Cleanups.
kegadmin: Clean up units editor.

Also closes #279.
Support some other standard keg sizes.

Closes #318.
core: Capture time zone with session data.

Previously, statistics were incorrectly computed against
the stored timezone (UTC), which was most evident in
day-of-week calculations.

Since the time zone setting can be changed by a manager,
it must be stored along with drink data.  For now, we do
so only on the session record.

Closes issue #199.
Update demo data.
core: Allow timestamp to be overridden in backend.
core: Fix backup tests.