Optimize/minimize bundle.js for production

[pdehaan]

Fixes #78

[pdehaan]

$ npm start (146 KB):

$ ls -lash public/*.js
146K Jun  9 13:33 public/bundle.js
 22K Jun  9 08:33 public/webcrypto-shim.js

npm run dev (744 KB -- w/ inline sourcemap):

$ ls -lash public/*.js
774K Jun  9 13:38 public/bundle.js
 22K Jun  9 08:33 public/webcrypto-shim.js

[pdehaan]

Disclaimer: This junk may or may not work. Browserify has never played nice w/ Uglify. That was supposed to be fixed via uglify-es, but I think npm5 is giving me semi-inconsistent results depending on how things get written to the package-lock.json.

🤷‍♀️