Disable ALL cookie warnings and hints

2018 - update: As stated by @ElegyD in the comments:

Prebake hans't been updated in 2 years. uBlock Origin now uses Fanboy's Cookiemonster List instead, you can enable it in the Annoyances category.

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Late 2015 update. The way to go nowadays appears to be with uBlock Origin, outperforming AdBlock and its variants.

It has an option to enable:

• EU: Prebake - Filter Obtrusive Cookie Notices‎

There is a Firefox/Chrome add-on called I don't care about cookies that will help you to remove these warnings from many thousands of, as it says, "infected" websites :)

If you use AdBlock or AdBlock Plus extension for Chrome, Firefox, etc. you can add a custom list filter to it that will block these pop-ups. Some ad blockers have built-ins list filters that block this and others annoyances.

I personally use Prebake. To use it just make sure you have one of the supported adblockers, access the site and click in the "Subscribe to the Prebake list filter".