Add a -h/--help option to the parser. Defaults to true.
When set to char.init, parameters to array and associative array receivers are treated as an individual argument. That is, only one argument is appended or inserted per appearance of the option switch. If arraySep is set to something else, then each parameter is first split by the separator, and the individual pieces are treated as arguments to the same option.
The assignment character used in options with parameters. Defaults to '='.
Single-letter arguments can be bundled together, i.e. "-abc" is the same as "-a -b -c". Disabled by default.
If set then argument names are case-sensitive. Defaults to true.
The string that conventionally marks the end of all options. Assigning an empty string to endOfArgs effectively disables it. Defaults to "--".
The option character. Defaults to '-'.