Remove unnecessary margins

Hi Harry,

I used the `flag` object in a project and I've some issue with vertical alignement. I believe that in most cases HTML elements present in `flag__body` will have bottom margin and create a bad visual rendering.

I forked your `flag` jsfiddle to illustrate my question : http://jsfiddle.net/florianbouvot/LY94Z/3/

I think that by default the `flag` object can remove the bottom margin of the last element in the body (like in the `media` object). What do you think ?

Thanks, Florian.