Add profile page

Adds a basic profile page. Next step is to allow users to update their
profile, but it gets a little dicey since changing the data has
unintentional consequences:

1. changing your email inadvertently changes your persona login
   and your gravatar profile image
2. the username is used to connect IRC statuses to a user account,
   so if your username needs to match your IRC nick

Given that, I didn't really want to fiddle with it without thinking
through it first.

r?