Add SiblingSequence to Node

[Ol1BoT]

Minor change to include SiblingSequence in the node

Why?

I use XMLQuery to construct XML documents from other formats such as JSON. This JSON would include a sequence property which instructs the order of the siblings.

when validating XML against an XSD the xsd:sequence cares about the ordering of it's children, so it's helpful to have a sibling sequence built into the node so that it can be sorted.