Add support for EU Cookie Compliance

In the EU google requires the following:

When using Google products that incorporate this policy, certain disclosures must be given to and consents obtained from end users in the European Union where EU data protection law requires such disclosures and consents.

See also http://www.cookiechoices.org/intl/en/.

Should this module include support for example the module EU Cookie Compliance → . Would it be fine to just notify the user that cookies are used to serve ads or does it require opt-in to serve adds with dfp? See section "Developers" on EU Cookie Compliance module page on how to implement opt-in.