base: removes redundant/obsolete HTML

* Removes meta content-type.
  http://code.google.com/p/doctype-mirror/wiki/MetaCharsetAttribute
* Removes obsolete meta element to specify document-wide language.
* Replaces deprecated link rev in favour of link rel.
  http://www.whatwg.org/specs/web-apps/current-work/multipage/obsolete.html#attr-link-rev
base: removes unnecessary closing <link> tag

* Closes link tag like the orphan tags they are.
base: removes redundant role=navigation on <nav> tag

* Removes redundant role on nav.
  "In the majority of cases setting an ARIA role and/or aria-* attribute
  that matches the default implicit ARIA semantics is unnecessary and not
  recommended as these properties are already set by the browser".
  See: http://www.w3.org/TR/html5/dom.html#aria-usage-note
  and http://www.w3.org/TR/html5/sections.html#the-nav-element
search: fixes missing space in search input attributes.