Remove unnecessary id

Encapsulating the feature in a angular directive let us avoid
setting global ids for elements.

directives/input.html

@@ -1,6 +1,6 @@
 <form class="form form-horizontal" ng-submit="sendMessage()">
   <div class="input-group">
-    <input id="sendMessage" type="text" class="form-control monospace" autocomplete="off" >
+    <input type="text" class="form-control monospace" autocomplete="off" >
     <span class="input-group-btn">
       <button class="btn btn-default btn-primary">Send</button>
     </span>