v0.8

• Adds SLAXML:xml() to serialize the DOM back to XML.
• Adds nsPrefix properties to the DOM tables for elements and attributes (needed for round-trip serialization)
• Fixes test suite to work on Lua 5.2, 5.3.
• Fixes Issue #10, allowing DOM parser to handle comments/PIs after the root element.
• Fixes Issue #11, causing DOM parser to preserve whitespace text nodes on the document.
• Backwards-incompatible change: Removes doc.root key from DOM when simple=true is specified.