Remove type attribute from default tag templates

`type` attribute for javascripts and stylesheets is neraly useless in HTML5:

  http://www.w3.org/html/wg/drafts/html/master/document-metadata.html#attr-link-type
  http://www.w3.org/html/wg/drafts/html/master/scripting-1.html#the-script-element

Resolves #37