rglondon | "Did you mean..." suggestions for page names

At the request of Nick, I've added a thingy to RGL that will show up when you try to view a nonexistent page — it will try to figure out what page(s) you might have been aiming for.

Nick asked for this after clicking on a truncated URL in an email — it should have pointed to Zeitgeist At The Jolly Gardeners, SE11 6AB but because of linewrapping in his email client it instead went to Zeitgeist At The Jolly Gardeners, SE1. The latter will now offer you the option of the former, instead of just telling you we don't have a page called "Zeitgeist At The Jolly Gardeners, SE1". Hopefully this is an improvement!

Please let me know if you see anything weird happening that seems to be a result of this change. Also, apologies, this relies on JavaScript to work, so if you have JavaScript turned off in your browser then it will just carry on doing what it used to do.