Users: cleanup and new tests.

- Move views to phonebook app.
- Move RegistrationMiddleware to phonebook app.
Users: Tests and bug fixes for tasks.
Update jenkins test command.
Add memcache module.
Add initial product_details.
Phonebook: Delete old tests.
Phonebook: Url namespace.
Phonebook: Cleanup
Remove deprecated UsernameWidget.
Add unidecode library to requirements.

AutoSlugField can generated better slugs for non-english strings if
unidecode package is installed.
Phonebook: Rename 'invite' db table to 'phonebook_invite'.
Phonebook: Add Invites to Admin Panel.
Phonebook: New tests.