added custom parser types (`positive_int`, `existing_file`).
created a `run` and an `info` subparser to distinguish better between the two
operation modes. Removed check of `N` (done by custom type).
Some cleanup of the parser done
Bug fix: the warning is to be given only if `old_param` is given
adapted to subparser when calling function `analyze`
function `recover_local_path` adapted to subparsers.
in function `initialise` indented all code supposed to `run`
`argparse.ArgumentParser` subclassed to use `io_mp.ConfigurationError` for
unified look of errors
Tests adapted to use the subparsers