Read takes the TOML configuration file at `path`, parses it into `dest` and then uses github.com/asaskevich/govalidator to validate the struct.

SetDuration converts a command line int to a duration, and stores it in the final config.

SetURL converts a command line string to a URL, and stores it in the final config.

ConfigOption is a complete description of the configuration of a command line option.

InvalidConfigError is the error that is returned when an invalid configuration is encountered by the `Read` func.

TLS represents a common configuration snippet for configuring TLS in a server process.