Vulcanize Polymer dependencies.
Revert "Added Polymer dependencies via Bower."

This reverts commit d9029eef1b899242a6d4b916bb9abfb08f592a48.

Conflicts:
	_layouts/page.html
Re-added bower config.
Ignore all bower files but web components polyfill.

The polyfill can't be vulcanized without breaking the Liquid tags, and
it can't be imported from a file without Liquid tags because it
polyfills the import.