Replace org.json by elemental.json

Include only the elemental.json stuff for JVM needed to run
GQuery JsonBuilders in server side without depending on anything but
gwtquery.jar.
No, this is the expected behaviour in JS as well, and this is the behaviour we had with previous org.json implementation, the same for boolean returning a valid false see below, o for string returning a toString of the content. 
These happens when we exactly know the signature of the method, I mean generic `Object get('foo')` returns the exact object contained, but `Integer getFoo()` has to return an integer always.