$wgAddGroups and $wgRemoveGroups, where the user must belong to a specified
group in order to add or remove those groups from themselves.
Backwards compatibility is maintained.
-* $wgEnablePersistentCookies has been added. Setting to false disables the
- setting of persistent cookies. Defaults to true.
* $wgRestrictDisplayTitle controls if the use of the {{DISPLAYTITLE}} magic
word is restricted to titles equivalent to the actual page title. This
is true per default, but can be set to false to allow any title.