set a title on the send button

directives/input.html

@@ -7,7 +7,7 @@
         <i class="glyphicon glyphicon-picture"></i>
         <input type="file" accept="image/*" multiple title="Send image" id="imgur-upload" class="imgur-upload" file-change="uploadImage($event, files)">
       </label>
-      <button class="btn btn-send unselectable"><i class="glyphicon glyphicon-send"></i></button>
+      <button class="btn btn-send unselectable" title="Send"><i class="glyphicon glyphicon-send"></i></button>
     </span>
   </div>
   <div id="imgur-upload-progress"></div>