Provide universal build for AMD, common.js and browser cjs.

No more `build:*`, just one `build` that creates `build/chaplin.js`.

@mehcode @knuton @molily fast review pls

1. AMD works as before.
2. Node common.js now actually works due to `module.exports`.
3. `window.Chaplin` is created for environments when there is no `module.exports` but there is `require`