Search should be sensitive to whole words

Summary: Chad noticed that, in the Period Games Space, he can't search for "Ur" to the get to The Game of Ur. That's because we currently have a three-char minimum, and that in turn is because we're doing simply substring matches. But if we had proper whole-word matching, and pushed those hits to the top, this would be a much more valid search term.

Once we implement this, remove the three-character minimum, or at least drop it to two.