title: Bootstrap: glyphicon-triangle-bottom not displaying
body: <p>I have a a simple instance of the bootstrap glyphicon-triangle-bottom 
  Placed in my rails view which I cannot get to display. It was working with a different glyphicon but not with this one. </p>
  
  <pre><code>#who_we_are  
    .text#who_text
      =link_to(who_we_are_path) do 
        %h2
          =t 'who_we_are_header'
        %p
          =t 'who_we_are'
        .glyphicon.glyphicon-triangle-bottom
  </code></pre>