Define INIT_PZVAL_COPY if not defined
Add json_nex_utf8_char for old PHP versions
Improve INIT_PZVAL_COPY definition
Replace zend_parse_parameters_none for compat with 5.2
Remove zend_function_entry const qualifier for compat with 5.2
Skip tests 003 and 004 for 5.3- due to changed props impl
Uso own checking for max digits length