fix(view): move nodes into the live document when cloning.

Closes #724

modules/angular2/src/facade/dom.dart

@@ -187,6 +187,9 @@ class DOM {
       node.nodeType == Node.TEXT_NODE;
   static bool isElementNode(Node node) =>
       node.nodeType == Node.ELEMENT_NODE;
+  static Node importIntoDoc(Node node) {
+    return document.importNode(node, true);
+  }
 }
 
 class CSSRuleWrapper {

modules/angular2/src/facade/dom.es6

@@ -219,6 +219,9 @@ export class DOM {
   static isElementNode(node:Node):boolean {
     return node.nodeType === Node.ELEMENT_NODE;
   }
+  static importIntoDoc(node:Node) {
+    return document.importNode(node, true);
+  }
 }
 
 export class CSSRuleWrapper {