Vulcanize!

Replacing the polymerPaperCompile custom task with grunt-vulcanize
https://github.com/uProxy/uproxy/issues/686

The one part that may seem confusing is that we have to call vulcanize twice.
Once to inline everything into the HTML
then once to extract all inline JavaScript into a separate vulcanized.js

It seems to be a bug with vulcanize that it doesn't know how to deal with merging JavaScript files that are already separate from the component HTML.
Do we need to delete the old polymer/popup.html file?