Add default command

[radubrehar]

Would be nice to have a command be the default command:

I'll use https://www.npmjs.com/package/translana to illustrate my point:

This is the help output for https://www.npmjs.com/package/translana

Usage:
 translana <command> [options]

Commands:
  translate  [--text] [--to] [--from] Translates text from source to target language
  version    Prints the version of the translator
  check      Checks slana is working

Options:
  --help     Show help  [boolean]
  --version  Show version number  [boolean]
  --from  [string]
  --to  [string]
  --text  [string]

For translana, it basically does translation. So I would like to be able to call translana like translana --text="How are you" --to=fr without specifying the translate command, which should be the default.