WICKET-4795 Wicket unit tests rely on hashmap iteration order

Upgrade https://github.com/douglascrockford/JSON-java
Change JSONObject#map from HashMap to LinkedHashMap to maintain the order

Update the tests expectations to the new order of the Ajax request attributes.
Fix two more tests that were broken due to the different order of entries in HashMap

Fix Wicket's build with JDK 1.8.0 b129