After c931d60c, default options were changed and we didn't want that.

Rewrite the code so that we have a clearer scheme:
 * all options of format are listed as FormatConfig attributes with default values
 * all values present in configuration file (.cfg) erase the previous options
 * all values present in command line erase the previous options

We use the special default argparse.SUPPRESS that removes totally the arg from arg dict so that only PRESENT options erase something