0. Write this file and documentation :)

1. Xerces
- implement more functionality

2. PHP-XML compatibility
- add missing functions:
utf8_decode
utf8_encode
xml_error_string
xml_get_current_byte_index
xml_get_current_column_number
xml_get_current_line_number
xml_get_error_code
xml_parse_into_struct
xml_parser_create_ns
x xml_parser_get_option
x xml_parser_set_option

xml_set_end_namespace_decl_handler
xml_set_external_entity_ref_handler
xml_set_notation_decl_handler
xml_set_processing_instruction_handler
xml_set_start_namespace_decl_handler
xml_set_unparsed_entity_decl_handler

- add aliases
