Support nil options on sub-command about cli-matic

[l3nz]

You are right, this is something I often do myself. 😄

Anyway, if you have something like:

{:app         {:command     "...."
                 :description "...."
                 :version     "180504.1"}

   :global-opts []

   :commands    [
                  {:command     "noparms"
                  :description "This is a command without parameters"
                  :opts        []
                  :runs        cmd_types}]})

it works with the current version (you need to have an empty vector, and cannot skip the :opts, by design).

Hope you will enjoy CLI-matic!