Querki should move away from hashbang URLs

Summary: It turns out that, even as we were moving towards hashbangs, the rest of the world was moving away from them.

Using the HTML 5 History API, we should be able to rebuild the system around more normal URLs, the same way, say, Gitter does it. See this post for some arguments of why we should do this.

Note that we will need to support hashbang URLs for a fairly long time, since they're out in the wild. But we should make them redirect to the new style.

Give some thought to how we detect and redirect spiders and bots in this new world. Currently, the way they do hashbang substitution is the key we watch; we're going to have to be smarter about noticing them and redirecting them to the raw controller.