requirements: Update some requirements

We were affected by a nasty South bug in legalpage migrations.
https://stackoverflow.com/questions/20446724
Accounts: Add a custom User class
pootle_store/views: Simplify user/profile logic
Accounts: Add User.display_name property
Accounts: Get rid of PootleProfileManager
Accounts: Get rid of the custom Profile admin
FIXME: Comment out broken code