Update to babel v7 and webpack v4
Remove runtime depend on corejs-2 which is
unsupported. Just switch to runtime which requires polyfills be
provided by the end user.
Remove NSP - the service is being shut down and the important bits
are built in to npm now.
istanbul has been replaced by the nyc runner. Update karma
Update yaml-loader and json-loader
Disable browser testing for now - we'll bring it back in a followup.
This patch creates a very simple index.js file which uses
ES2015. It then creates a very simple Babel compile step
which converts this into a usable library.