SQUASH ME: feat($http): specify the JSONP callback via the callbackParam config value

Author: petebacondarwin

src/ng/http.js

@@ -875,11 +875,11 @@ function $HttpProvider() {
     <button id="samplegetbtn" ng-click="updateModel('GET', 'http-hello.html')">Sample GET</button>
     <button id="samplejsonpbtn"
       ng-click="updateModel('JSONP',
-                    'https://angularjs.org/greet.php?callback=JSON_CALLBACK&name=Super%20Hero')">
+                    'https://angularjs.org/greet.php?name=Super%20Hero')">
       Sample JSONP
     </button>
     <button id="invalidjsonpbtn"
-      ng-click="updateModel('JSONP', 'https://angularjs.org/doesntexist&callback=JSON_CALLBACK')">
+      ng-click="updateModel('JSONP', 'https://angularjs.org/doesntexist')">
         Invalid JSONP
       </button>
     <pre>http status code: {{status}}</pre>