Created by: necolas
Added some extensions and files to the .gitignore file. Based on what we provide in H5BP.
Deleted some unnecessary properties in the clearfix mixin. There are IE7-targeting hacks that are present within the pseudo-element selectors, but IE7 doesn't support the :before/:after pseudo-elements so you can safely omit them.
Removed the WebKit-OSX search[type="search"] cancel button pseudo-element (port over from recent update to normalize.css).
Hope this is helpful.