Allow multiple subcommands

[Boscop]

I would really like to be able to do the following:

prog <general_args..> cmd1 <cmd1_args..> cmd2 <cmd2_args..>

Because my program needs to have a CLI to run commands seq sequentially, without duplicating all the fields in each subcommand: Currently the cli for that looks like:

prog <general_args..> cmd1 <cmd1_args..> --cmd2 <cmd2_args..>

Which makes everything really awkward, especially because I have to duplicate the fields and support chaining and calling of cmd2 directly. And now I want to be able to chain arbitrary number of commands, this gets very hairy! So please, can we allow multiple subcommands? :)