Separate js files

This puts all scripts into separate files instead of generating them in PHP

cc @BYK @chazcb
People were reporting many Google Webmaster 404's because google would read `.../embed.js` as `theirsite.com/embed.js`

@BYK thinks we can fool them by hard-coding the domain with `.disqus.com/embed.js` instead. We shouldn't need to dynamically change the domain at this point anymore anyways.