Intl support

As the current polyfill for ECMA-402 Intl under https://github.com/andyearnshaw/Intl.js/ is no longer maintained (see https://github.com/andyearnshaw/Intl.js/issues/341) I would like you to reconsider adding support for this spec.

Is size the only problem for supporting this wiithin core-js?

Thanks a lot for all your efforts.