Use solr's highlighting.

It is simple to turn on, less wrong than what we had, and is being
actively worked on by solr developers.
Merge branch 'master' of ssh://gerrit.wikimedia.org:29418/mediawiki/extensions/CirrusSearch
Squash accented characters.

Note that we have to be careful with the order in which the squashing is
done so résumé doesn't get stemmed like resume.