code: public static Schema minusFields(Schema schema, String... minusFields) {
  		return minusFields("minusSchema" + (COUNTER++), schema, minusFields);
  	}
docs: Creates a new schema which has exactly the same fields as the input Schema minus the field names
  that are specified as "minusFields". This is equivalent to calling {@link #subSetOf(Schema, String...)}
  with the list of Fields that must remain, but instead here we specify the fields that should NOT remain.
  <p>
  The name of the schema is auto-generated with a static counter.