code: public static <D,S> IJMapper<D, S> getMapper(final Class<D> destination, final Class<S> source){
  		return getMapper(destination,source, undefinedConfig());
  	}
docs: Returns an instance of JMapper from cache if exists, in alternative a new instance.
  
  @param destination the Destination Class
  @param source the Source Class
  @param <D> Destination class
  @param <S> Source Class
  @return the mapper instance