Adds rels for user profile links to followers, following, and updates.

According to ALPS, the following rels are used on <a> tags:

* **messages-me**: Applied to an A tag. A reference to a list representation
of all the messages posted by the designated user.

* **users-friends**: Applied to an A tag. A reference to list representation
of the designated user's friend users.

* **users-followers**: Applied to an A tag. A reference to list representation
of the users who follow the designated user.

They indeed point to lists of ```li.user```'s so I've added them.