Remove unwanted dependencies

[emadalam]

Now that the AppleTV platform is stable enough, it would make sense to get rid of the redundant dependencies and rely on ES6 or related resolutions. Read #15 (comment) and #15 (comment).

• remove babel-polyfill
• evaluate and replace Promise alternatives
• evaluate and remove lodash (use custom stripped down build if required)
• evaluate and remove pubsub-js