Cleanup: Get rid of an unused import
Cleanup: Update an outdated docstring
Unit: Use 'url' to identify the user url, rather than 'profile_url'
Accounts: Use AUTH_USER_MODEL in all User migration relations
initdb: Create directories before creating essential users

This fixes the issue of Directory.objects.root being called before
other models are loaded
Accounts: Use settings.AUTH_USER_MODEL in PootleProfile as well
Accounts: Get rid of is_staff everywhere
Accounts: Add a custom User class
Accounts: Use full_name instead of first/last name
pootle_store/views: Simplify user/profile logic
Accounts: Move gravatar_url() to User model
Accounts: Get rid of PootleProfileManager
Accounts: Get rid of the custom Profile admin
Accounts: Move PootleProfile.get_unit_rows to User.unit_rows
Accounts: Move UserForm to accounts.forms
Accounts: Move User.post_save logic to accounts

This lets us avoid a call to get_user_model() before the app registry is ready.
docs: Get rid of a now-irrelevant warning in the api docs
pootle_store: Pass User instances instead of PootleProfile wherever possible
Store: Use user instead of profile in get_alt_src_langs()
Accounts: Get rid of some unnecessary calls to get_profile()