Move away from fully_reduces_to_null to rule_position, fixed some bugs. Have not fixed all, still looks up unkown key-value for the full kraken parse test.

tests/grammer2.kgm

@@ -7,8 +7,10 @@ c = "a" | d ;
 d = e post_null post_non_null inherit_null ;
 inherit_null = e | post_non_null ;
 e = ;
-e = f | ;
+e = g ;
+#e = e | g ;
 f = ;
+g = f ;
 post_null = "hi" ;
 post_non_null = "bye" ;
 rec = "hmm" rec | ;