ES6 has no "inline module" syntax

[getify]

Unfortunately, related to my research around #42, I discovered via twitter conversation with @dherman that my treatment of ES6 modules w/ inline syntax is invalid as of Sept 2013, when that syntax was rejected from ES6.

Update the syntax and the discussion around it in Chapter 5: "Future Modules" according to the more recent accepted syntax: https://github.com/jorendorff/js-loaders/blob/master/specs/es6-modules-2013-12-02.pdf

/cc @bmacdonald-oreilly @othiym23