Improve documentation and npm metadata for findability

I spend about an hour and a half today messing around with the wrong module, thinking that [`backbone-localstorage`](https://www.npmjs.org/package/backbone-localstorage) was the one I wanted because it was the first one I found on [https://npmjs.org](npm) using the search term "backbone localstorage". It is not a CommonJS module, so it was not behaving as I expected it to. Hopefully these changes will help prevent others from making the same mistake in the future.