Feature: Parse additional config file information to be merged into existing config object

[kesmit13]

Maybe this is possible already, but it isn't obvious. I'd like to parse arguments and config files at startup, but then add an additional config (either file or string contents of file) at a later time. The existing config would be updated with the settings from the new information.

[bw2]

This is a hack, but should work:

parser = configargparse.Parser(..)
initial_args = parser.parse_args()

parser._default_config_files.append("config_file2.ini")
updated_args = parser.parse_args()

If this is useful (especially to more than one person) I could add a method like add_config_file(..) to the api.