- Rewrote the profile module:

   + Added a 'created' field to the users table and renamed the 'timestamp'
     fied to 'changed' (cfr. node table).  Update.php will try to determine
     a 'created' timestamp for existing users.

   + The profile module no longer uses serialized data but has its own set
     of tables.  Known existing profile data is migrated by these new tables.
       TODO: migrate the birthday field.

   + The profile fields can be grouped, and within each group, profile fields
     can be sorted using weights.

   + The profile pages can be themed.

   + The profiles can be browsed based on certain properties/settings.

   + Change the _user hook: (i) 'private_view' and 'public_view' are merged
     into 'view' as there are no private fields and (ii) 'edit_form' has
     been renamed to 'edit'.

   + Avatar handling has been refactored and is now part of the user module.
     The users table has a dedicted 'picture' field.

   + Simplified the way themes should use display/visualize pictures or
     avatars.

   + Made it possible for administrators to replace or delete avatars.

   + ...

  I hope this make for a good base to build on collectively.