[Systems] Mediawiki 1.16

[Bernie Innocenti]

I've upgraded the wiki-devel.sugarlabs.org to Mediawiki 1.16. Please,
test. If it seems to work well I'll upgrade also wiki-testing and wiki.

There were no changes to the UsabilityInitiative extensions, so I'd
expect the AJAX editor to be still as broken as it was when I disabled
it.

-- 
   // Bernie Innocenti - http://codewiz.org/
 \X/  Sugar Labs       - http://sugarlabs.org/