Fix "Invalid calling object" in Edge and ES6 syntax error in IE

[AlexeyMz]

Included changes:

• Wrap indirect setImmediate into function to prevent "Invalid calling object" error in IE/Edge (due to a bug it's an error to call setImmediate indirectly).
• Fix babel-loader include condition to transpile rdf-canonize dependency.

This PR fixes issue #319

[AlexeyMz]

Hi @davidlehn @dlongley
I rebased PR on latest develop to pass the tests. Is there anything else preventing the PR to be merged?

[andreikun]

We encountered same issue and we end up importing from dist instead of primary entrypoint something like this:
const jsonld = require('jsonld/dist/jsonld.js');

Unfortunately, we still experience "Unhandled promise rejection TypeError: Invalid calling object" and this fix would really help us as we do not want to start using babel loader for 3rd party libraries and node modules.