Add support for nested subcommands

[novastosha]

Add support for ways to nest subcommands

One of the important implementations can be by nesting a subcommand that only has arguments and no options

Which would result in a syntax like this: test.exe subcommand <option> nested_subcommand <options/arguments>

[JordanMarr]

Show me how you would expect your example above might look if this was implemented.