Pass compilation meta data to the client-side runtime

[markfinger]

It'd be useful to have more contextual information available when rigging up the runtime.

The immediate use-case I can see is denoting that interface modules are stateless. Eg: when importing a CSS file, image, etc, the dev runtime should know ahead of time that it can replace them when appropriate. This would enable us to stop injecting module.hot.accept() and remove the tight-coupling to babel's ES -> CommonJS flags.