New library: argparse, for parsing CLI arguments

[Andrey Zherikov]

On Tuesday, 19 October 2021 at 14:06:21 UTC, Steven Schveighoffer 
wrote:
> Just nitpicks. Like allowing `@NamedArgument` without 
> parentheses. Or using `@NamedArgument("b", "banana", "ban")` 
> instead of `@NamedArgument(["b", "banana", "ban"])`

I did array because I think it makes sense to have 
`@NamedArgument(names, help_text)` as a shortcut for 
`@(NamedArgument(names).HelpText(help_text))` for CLI.