zurb/foundation — pull request #1649 by gavinballard (2013-03-02 03:26:18+00:00)
Title: Fix for #1648 - Button with postfix or prefix does not render text at correct height

As above. I'm not 100% familiar with Zurb's patterns, so unsure if this overriding of an override is considered good practice or not - but it appears to fix the issue.