6.4

• Add method facturx_schematron_get_codedb_xml_file(level) to get the CodeDB XML file of the Factur-X schematron for a specific level
• Add argument saxon_server_codedb_base_url to customize the URL where the Saxon Server can get the CodeDB XML file. This is an alternative to the argument saxon_server_codedb_dir with the same purpose: reduce latency of Factur-X schematron check (the base Factur-X schematron XSLT file depends on an external CodeDB XML file).