Revert removal of compare nesting

Since we want the user to be able to pass a negative comparison function, the extra layer of wrapping is now needed

src/core/matchers/toContain.js

@@ -2,10 +2,13 @@ getJasmineRequireObj().toContain = function() {
   function toContain(util, customEqualityTesters) {
     customEqualityTesters = customEqualityTesters || [];
 
-    return function(actual, expected) {
-      return {
-        pass: util.contains(actual, expected, customEqualityTesters)
-      };
+    return {
+      compare: function(actual, expected) {
+
+        return {
+          pass: util.contains(actual, expected, customEqualityTesters)
+        };
+      }
     };
   }