Fix document.importNode in IE9.

document.importNode exists in IE9 but fails. Just fails. It's not implemented, just says it's there and fails when called *sigh*.

core.js

@@ -12,7 +12,7 @@
  * "THE BEER-WARE LICENSE" (Revision 42):
  * <julien.cigar@gmail.com> wrote this file. As long as you retain this notice
  * you can do whatever you want with this stuff. If we meet some day, and you
- * think this stuff is worth it, you can buy me a beer in return Julien Cigar.
+ * think this stuff is worth it, you can buy me a beer in return.
  * ----------------------------------------------------------------------------
  */
 
@@ -394,10 +394,13 @@
             deep = true;
         }
 
-        return document.importNode ?
-        document.importNode(node, deep) :
-        (function(node, deep) {
-
+        /* Note: document.importNode exists in IE9 but fails. Just fails. It's
+         * not implemented, just says it's there and fails when called.
+         */
+        try {
+            return document.importNode(node, deep) :
+        } catch(e) {
+            return (function(node, deep) {
                 /* Returns an integer code representing the type of the node. */
                 var NodeTypes = {
                     ELEMENT_NODE : 1,
@@ -461,6 +464,7 @@
                 }
             })(node, deep);
         }
+    }
 
     /* Yeti.DOM.firstElementChild
      * Returns a reference to the first child node of that element which is of