MDL-49811 lib: Added js to skiplinks

I have added a JS module to handle skiplinks to send
the focus to the end of the block. This improves the function
and allows the user to better tab through the page.

lib/javascript-static.js

@@ -1828,3 +1828,17 @@ M.util.load_flowplayer = function() {
         document.getElementsByTagName('head')[0].appendChild(fileref);
     }
 };
+
+/**
+ * Initiates the listeners for skiplink interaction
+ *
+ * @param {YUI} Y
+ */
+M.util.init_skiplink = function(Y) {
+    Y.one(Y.config.doc.body).delegate('click', function(e) {
+        e.preventDefault();
+        e.stopPropagation();
+        Y.one(this.getAttribute('data-target')).focus();
+        return true;
+    }, 'a.skip');
+};