Test failure: `tests::settings`

Created by: xTibor

This test fails at the moment due to some incorrect behaviour of the add_setting_default method. I noticed this problem via the dd command, it throws panicks when the bs or count arguments are omitted.

Log:

failures:
---- tests::settings stdout ----
        thread 'tests::settings' panicked at 'assertion failed: parser.get_setting("of") == Some(String::from("foo"))', src/lib.rs:516:8