add yySetValue function so that child class can set _yyValue too.  Also remove the junk comment for yyPopLookahead.
add yySetValue function so that child class can set _yyValue too.  Also remove the junk comment for yyPopLookahead.
miguel01997/cookcc,miguel01997/cookcc,coconut2015/cookcc,coconut2015/cookcc,coconut2015/cookcc