code: public InputStream openStream(final String filename) throws IOException {
  		if (zipArchive != null) {
  			// lade aus zip datei
  			ZipEntry entry = null;
  			int index = 0;
  			String name = filename;
  			do {
  				name = name.substring(index);
  				entry = zipArchive.getEntry(name);
  				index = name.indexOf('/') + 1;
  				if (index == 0) {
  					index = name.indexOf('\\') + 1;
  				}
  			} while (entry == null && index > 0);
  			if (entry != null) {
  				logger.info("Opening stream to '{}' in zip archive...", name);
  				return zipArchive.getInputStream(entry);
  			}
  		}
  		return ResourceLoader.getInputStream(filename);
  	}
docs: Returns an input stream the file with the specified name. If this {@link Configuration} was
  loaded from a zip file, and {@link InputStream} to zip entry with the specified name is
  return. Otherwise, {@link ResourceLoader#getInputStream(String)} is used.
  
  @return The stream