Cannot load with requirejs: johnson.js: "Uncaught ReferenceError: module is not defined"

The dependencies 

elementary-circuits-directed-graph

and 

strongly-connected-components

do not have headers that are compatible with requirejs.

Related:

https://github.com/antoinerg/elementary-circuits-directed-graph/issues/19

https://github.com/mikolalysenko/strongly-connected-components/issues/5
