Fix tooltip error with draggable columns

- added draggable columns option to autotooltips example
- patched autotooltips plugin as per mleibman/SlickGrid#1056
- the HTML encoding mentioned in the pull request has been removed already in the current master
- thanks to B1nke

examples/example-autotooltips.html

@@ -35,6 +35,7 @@ <h2>View Source:</h2>
 
 <script src="../lib/jquery-1.11.2.min.js"></script>
 <script src="../lib/jquery.event.drag-2.2.js"></script>
+<script src="../lib/jquery-ui-1.11.3.min.js"></script>
 
 <script src="../slick.core.js"></script>
 <script src="../slick.grid.js"></script>
@@ -53,7 +54,7 @@ <h2>View Source:</h2>
 
   var options = {
     enableCellNavigation: true,
-    enableColumnReorder: false
+    enableColumnReorder: true
   };
 
   $(function () {

plugins/slick.autotooltips.js

@@ -69,7 +69,7 @@
     function handleHeaderMouseEnter(e, args) {
       var column = args.column,
           $node = $(e.target).closest(".slick-header-column");
-      if (!column.toolTip) {
+      if (column && !column.toolTip) {
         $node.attr("title", ($node.innerWidth() < $node[0].scrollWidth) ? column.name : "");
       }
     }