HTML5 History

Altered Sugarcane so that it now uses HTML5 history management instead
of hashchanges. This means, apart from keeping the URL tidy, a number of
non-deterministic non-link-based state changes (setting a random number,
using a custom macro) are now properly remembered when you go back in
the browser. (One downside, though, is that you can no longer bookmark a
particular page to 'save your game'.)

The hashchange code still remains as an IE9 fallback.