Inspecting the source code, it's possible to see that core.js involves several independent components. We could split the file into several other files like:

• core/utilities.js: in which we could have functions like hasOwn or objectType.
• core/config.js: in which we could have the config object.
• core/reporter.js: with the logging callbacks...

I think this could help removing the circular dependencies in the project, and that would help to accomplish things like #707 and #735