Asset management system, Subscribe form validation.

So this commit introduces the Asset management system.
You can specify global assets in the AssetLib.php static arrays,
or before rendering a view you can opt to add specific pieces of
assets. Which is cool.

There's also a nifty form validator now for the Subscribe page.
This checks your inputs as you type and makes sure you're doing
it right. And by right, I mean that your phone number is in the
proper format for everything to work well.