Update VRaptorXStream.java

Relaxing class giving possibilies to override protected methods
Update XStreamBuilderImpl.java

Relaxing recursive attribute to override MapWrapper in VRaptorXStream.class
Update XStreamBuilderImpl.java

Reverting recursive visibility to private and add method to return actual value
Update VRaptorXStream.java

Reverting vraptorMapper visibility
Merge pull request #679 from jlemes/xstream-mapper

adding isRecursive method on XStreamBuilderImpl