Adding a browser-based demo

Hey everybody,

I just added a browser-based version of the demo, so you can now play it on the page here. Until I have an Android and iOS versions in place, this should make it accessible on mobile as well. I don't currently plan on putting out the full version in a browser-based capacity, but for the demo I think this ought to require a little less commitment for people who just want to take a peek. 

Just keep in mind that if you play in the browser, your game progress will be saved in the browser, so if you regularly clear all your browser data or anything you might risk losing it. The demo isn't that long, so I doubt it will be an issue, but I'd hate for anybody to lose progress.

Thanks!