Parser initial commit
A few bugfixes
Updated parse_xml_instance method to use new EntityParser class from utils
Updated to reflect recent changes for parse_xml_instance output
Added optional check_version parameter to parse_xml_instance method
Updated for parse_xml_instance updates
Updated for parse_xml_instance updates
Updated for parse_xml_instance updates
Added imports for parser classes
Added ability to add namespaces parsed upon input in to_xml() and to_xml_file(); updated _get_namespace_def accordingly