Removed duplicated 'external' icon.

Removed duplicated 'external' icon from example and code section.
Also delete the duplicated 'comments'  icon form the code section I left out from my previous commit c8023c6

Author: anantoghosh

server/documents/elements/icon.html.eco

@@ -56,7 +56,6 @@ themes      : ['Default']
         <div class="column"><i class="delete calendar icon"></i>Delete Calendar</div>
         <div class="column"><i class="external square icon"></i>External Square</div>
         <div class="column"><i class="external icon"></i>External</div>
-        <div class="column"><i class="external icon"></i>External</div>
         <div class="column"><i class="eyedropper icon"></i>Eyedropper</div>
         <div class="column"><i class="feed icon"></i>Feed</div>
         <div class="column"><i class="find icon"></i>Find</div>
@@ -122,14 +121,12 @@ themes      : ['Default']
         <i class="comment icon"></i>
         <i class="comments outline icon"></i>
         <i class="comments icon"></i>
-        <i class="comments icon"></i>
         <i class="copyright icon"></i>
         <i class="creative commons icon"></i>
         <i class="dashboard icon"></i>
         <i class="delete calendar icon"></i>
         <i class="external square icon"></i>
         <i class="external icon"></i>
-        <i class="external icon"></i>
         <i class="eyedropper icon"></i>
         <i class="feed icon"></i>
         <i class="find icon"></i>