rename prolog_parser_rebis to prolog_parser

also remove remaining extern crate statements that slipped through earlier

src/machine/arithmetic_ops.rs

@@ -1,7 +1,7 @@
 use divrem::*;
 
-use prolog_parser_rebis::ast::*;
-use prolog_parser_rebis::clause_name;
+use prolog_parser::ast::*;
+use prolog_parser::clause_name;
 
 use crate::arithmetic::*;
 use crate::clause_types::*;