Add PhoneFormat.js (direct port from extension).

- TODO: This will need to be made common.js portable for browserify's require.
Add in port of PhoneFormat.js.

- Use new polymber-build nobrowserify feature.
- Did some refactor of the negativeFilters to handle the new match
  approach for multiple numbers in an element.
- :memo: Fixed some markdown formatting.
Reference polymer-build `nobrowserify` branch.

- TODO: Try to get this feature merged into polymer-build's master.