Media: flag object to vertically align media content with media image

Created by: stubbornella

My team and I are interested in extending the media object to create @csswizardry's Flag object. The rough idea is that we have designs that call for an image to be vertically centered with respect to it's content, like so:

You can read more about it here:

http://csswizardry.com/2013/05/the-flag-object/

Would you be open to a PR?

Cheers, @stubbornella, @jenndodd, @gpleiss, & @bebepeng