Add support for Bison 3.x

* Add TSRMLS_[CD]N macros
* Use %pure-parser instead of %pure_parser
* Use %error-verbose instead of YYERROR_VERBOSE
* Use %parse-param and %lex-param instead of YY(PARSE|LEX)_PARAM
* Always pass a TSRMLS parameter to parser functions; pass NULL when !ZTS