code: public static <T> ListDataKey<T> create(String name, GenericType<T> genType, boolean allowNull) {
          return create(name, genType.getRawType(), allowNull);
      }
docs: creates a list data key with the given name and type. If you allow for null values
  then the list might as well be null. Otherwise only actual lists are allowed to be
  stored and retrieved.
  
  @param <T> the type of the value
  @param name the name of the key that is stored in the xdata file
  @param genType the genericType of the class of the type
  @param allowNull if null is allowed or not
  @return