Added toNamespaceAwareDocument which delegates to a real XML parser
Extracted XmlNamespacesTest
Extracted XmlNamespaceTest
Do not produce XML declaration for toString/toPrettyString
Removed debug code
Simplified toDocument to not be namespace-aware
Refactored XmlNamespaceTest: test the element and attribute together in each scenario
TODO notes
Unit tests for XmlSchemaValidator
Added XmlDocumentGenerator.toInputStream()
Refactored: extracted IOUtil