Add a user directory page

For security reasons, I've omitted the users.php page. Mainly all it
does is call a DB, and grab the information from the URL provided.

Basically, tox.im/user/shortenedid is taken, searched within a DB, and
the info is taken. Once I can audit users.php and make sure everything
is okay, I will release it, but for safety's sake, it's closed-source.