ONLY_LOCAL_NAMESPACES seems not to work

If you call ElementNode::getNamespaceBindings() on a store::Item, and pass the NsScoping value ONLY_LOCAL_NAMESPACES, you will still get namespace bindings declared by parent elements. For instance, if you have the query

 <foo:Employee xmlns:foo="http://www.opencsx.org/schema"><foo:Name>Luis</foo:Name><foo:Salary>10000000</foo:Salary></foo:Employee>

and you get the store::Item for <foo:Name>, you will get the binding for xmlns:foo.

This results in redundant information being stored when serializing to CSX, and also prevents certain CSX format optimizations.