Utility to generate all the "externals" for your webpack config.
Since RxJS is ever-changing, this removes the need to maintain a list, instead generating it on the fly.
Latest version only works with v6+ import paths, NOT the older v5 deep paths. Use v1.1.0 version for rxjs v5 Requires webpack v2
;externals:// other externals here;
Example of v6 imports this supports
;;of1 2 3;
Remember, this version does NOT support the older deep imports