backend logic for auto generated required items (new elem insertion) created. JS logic missing. Refs #35
refactor: createNode + added logic for auto generating of required children, refs #35, refs #40.

This commit contents bug in generating correct xpath for second and more elements. Need to be rapaired. XPath for generated label and value differs!
adjusting XML tree line height, fixes #41
repaired creating new nodes (repaired generated xPath), including auto generated required items, closes #35, closes #40