code: static public InputStream replace(File file, File props, Properties base, boolean env) throws IOException, SubstitutionException{
  	if (env) return replaceProperties(replaceEnv(file), loadProperties(base, props));
  	else return replaceProperties(file, loadProperties(base, props));
      }
docs: Creates an InputStream containing the document resulting from replacing template
  parameters in the given file.
  @param file The template file
  @param props The properties file
  @param base Properties that should override those loaded from the file
  @param env If properties from System.getenv should also be used
  @return An InputStream containing the resulting document.