- $newpassword: the desired new password
- &$errormsg: set this to an error message if the password could not be changed. If the password was changed, leave this as false
+CanUserChangeField: Determines if a user is allowed to change a specific profile field
+- $nickname: nickname of the user who would like to know which of their profile fields are mutable
+- $field: name of the field the user wants to change (nickname, fullname, password, avatar, etc)
+
UserDeleteRelated: Specify additional tables to delete entries from when deleting users
- $user: User object
- &$related: array of DB_DataObject class names to delete entries on matching user_id.