fix for infinite loop in retrieveScope with jQuery + specs

- retrieveScope run into infinite loop if called on DOM tree
  that doesn't contain scope reference (happens only with jQuery)
- added missing specs for retrieveScope function

src/Compiler.js

@@ -75,7 +75,7 @@ Template.prototype = {
 function retrieveScope(element) {
   var scope;
   element = jqLite(element);
-  while (element && !(scope = element.data($$scope))) {
+  while (element && element.length && !(scope = element.data($$scope))) {
     element = element.parent();
   }
   return scope;