Revert "exposing NotSchema#mustNotMatch property, as requested in #53"

This reverts commit de2b284.

Author: erosb

core/src/main/java/org/everit/json/schema/NotSchema.java

@@ -56,10 +56,6 @@ public NotSchema(final Builder builder) {
         this.mustNotMatch = requireNonNull(builder.mustNotMatch, "mustNotMatch cannot be null");
     }
 
-    public Schema getMustNotMatch() {
-        return mustNotMatch;
-    }
-
     @Override
     public void validate(final Object subject) {
         try {

core/src/main/java/org/everit/json/schema/loader/LoadingState.java

@@ -5,7 +5,6 @@
 import org.everit.json.schema.SchemaException;
 import org.everit.json.schema.loader.internal.TypeBasedMultiplexer;
 import org.json.JSONObject;
-import org.json.JSONPointer;
 
 import java.net.URI;
 import java.util.Map;
@@ -25,7 +24,7 @@ class LoadingState {
 
     URI id = null;
 
-    JSONPointer pointerToCurrentObj;
+    String pointerToCurrentObj;
 
     final Map<String, ReferenceSchema.Builder> pointerSchemas;