Enable browserify build process

[bcomnes]

We need to get yo-yoify into the build process before we release. @blahah released a nice transform that makes this work nicely in electron by prefixing require calls to built in to be window.require so that electron and other built in node calls still 'just work'.

• npm start: runs hyperamp in dev mode. Uses buds for building a bundle without making a mess on disk.
• npm run build: builds hyperamp without any additional optimizations. Does not create DMG
• npm run prod: builds hyperamp with a few optimizations and creates a DMG.

Closes #174

[ungoldman]

In the past I've done the following to avoid maintaining two nearly identical index.html files:

<script>
    if (process.env.NODE_ENV === 'development') {
      let bundle = document.createElement('script')
      bundle.src = 'http://localhost:8283/bundle.js'
      document.body.appendChild(bundle)
    } else {
      require('../bundle/bundle.js')
    }
  </script>

Otherwise LGTM

[bcomnes]

We should do that.

[ungoldman]

@bcomnes see #245