'My score' is better than 'Your score', given re:me.
Paranoia: Behave correctly if there are no reviewScoreNames.

Even though there are.
Correctly support 'overall-merit:3' searches.

preg_quote() didn't use to quote dashes, now it does (as of PHP 5.3.0).
Support multiple sort: keywords.

E.g. sort:overall-merit sort:title sorts first by overall merit, then
title.
Support complex sorters, such as 'sort:"overall merit by variance"'.