Okay, the basic version of the search facility is now written and live.

The search should be fairly robust; there's only a few of things that still really need sorting out:

1) The word search is just a brain-dead wildcard substring match. It could be much better.
2) Needs a "sort by" facility. But there's not many sentences in the database yet, and I need to have some time off this evening, so that can wait!
3) Non-Javascript clients won't be able to rate sentences which appear in the search results. I just need to nick the handling of that from
the Browse Sentences page, but I think I should be starting to break that kind of stuff out into a function.

Still, it's basically working, and looks okay, I think.