code: public static ParticleSystem loadConfiguredSystem(InputStream ref, Color mask)
  			throws IOException {
        return loadConfiguredSystem(ref, null, null, mask);
  	}
docs: Load a set of configured emitters into a single system
  
  @param ref
  The stream to read the XML from
  @param mask The mask used to make the particle image transparent
  @return A configured particle system
  @throws IOException
  Indicates a failure to find, read or parse the XML file