added racket cloc plugin and simplified PATH

.scripts/cloc-z.txt

@@ -3,6 +3,11 @@ zepto
     filter remove_inline ;.*$
     extension zp
     3rd_gen_scale 1.25
+racket
+    filter remove_matches ^\s*;
+    filter remove_inline ;.*$
+    extension rkt
+    3rd_gen_scale 1.25
 JSX
     filter remove_matches ^\s*//
     filter call_regexp_common C