Revert "US43001: Replace libxmljs with node-xml-lite in XML reader functions."

This reverts commit 5ea8c90c59244fe2bbf7cd29accf5de588b1b272.
US43001: Replace node-xml-lite with elementtree.
Merge pull request #9 from Brightspace/nstonehouse/remove-libxmljs

Nstonehouse/remove libxmljs