[Mediawiki-i18n] Updates to messages since 28.11.2006

[helix84]

* New
undosucceeded
explainundosucceeded
undo-summary

Tip: Did you know that apart from so called "core messages", there are
also extensions, which can be translated? You'll find them in SVN at
http://svn.wikimedia.org/svnroot/mediawiki/trunk/extensions
Those which can be localized will have a file ending "i18n.php". They
contain strings for all languages. After you translate them, submit
patches to bugzilla
http://bugzilla.wikimedia.org/