Full text search in help now works

This news is a couple of days old, but I should mention that Factor's online help now supports full text search. At the moment, it performs exact matches after stemming, and uses a simple ranking algorithm to rank results based on the number of search terms that appear, with a special bonus given to terms appearing in the title. In the next round of improvements, I will investigate better ranking algorithms, and implement Levenshtein edit distance matching. For now this is good enough, and I'm going to focus on bug fixes as I get ready to release Factor 0.83.