Single file fetching with multiple modules

[thanpolas]

The current implementation of multiple modules requires that all the separate modules are pre-build before they can be fetched by the core when on development.

To implement such a workflow requires a build-step for each modification that happens in any of the modules. While this flow can easily be implemented with nowdays automation tools, it is far from optimal.

To solve this issue and enable single file fetching for all multiple modules the goog.provide and goog.require functions would need to be enhanced.

Clap hands if you need this done =)