Django 1.7

Substantial refactor to achieve Django 1.7 update.

### Fixtures

* These are removed, and replaced with [Data migrations](http://django.readthedocs.org/en/1.7.x/topics/migrations.html#data-migrations). This allows for consistent behaviour with regards to model and dependency loading for tests and live data

### Migrations

* Old migrations have been scrapped, and South dependency has been removed
* New migrations including data migrations have been created for all apps

### TEST_RUNNER

* This was a change in Django 1.6, but is affected by the deprecation cycle in 1.7. Consequently ```TEST_RUNNER``` is now defined in settings.py

### API change

* Quick change to ```cc_kapi``` keyboard ```DELETE``` function. This should not provide feedback to the user, that should be done within the client-side javascript.

### Note re database changes

* Users should note that this potentially will cause breakage if this change is pulled into a deployed cellcounter instance *without* complete up-to-date migrations at time of merge. Consequently, a new release tag has been created at 0.9.0. If any user has only a partially migrated instance (unlikely) they should update to release 0.9.0 and apply all migrations, then continue tracking master thereafter.