<base> tag does not need closing slash in HTML5 as it is a void element.

`<base />` Is perfectly valid in every browser so this is really just removing it cause it's frivolous. Pretty dumb of me to care...but for whatever reason I do.

References:
http://dev.w3.org/html5/spec-author-view/syntax.html#syntax-start-tag
http://www.w3.org/html/wg/drafts/html/master/single-page.html#void-elements