The current incarnation of `bob config` does not allow one to remove variables from the configuration file. A subcommand to `unset` a variable would be welcome - the command should also allow for the file to be cleared of all variables starting with a substring. E.g.: ```sh $ bob config unset bob.db.atnt #removes everything concerning bob.db.atnt ``` Other than that, it would be beneficial if the documentation of this command followed the changes in #61 (i.e., documenting options and arguments via the epilog and `help` entries, followed by examples.