Re: test for nil

[leorize]

Yea, that part is rather misleading, but it's due to how `docopt` [convert that 
to 
string](https://github.com/docopt/docopt.nim/blob/65da8739a7534b8d78249a90778e1b38d4bdcf5c/src/docopt/value.nim#L82).
 Looks the the correct way to check for that is:
    
    
    if args["--wid"].kind == vkNone
    
    
    Run

or
    
    
    if not args["--wid"] # vkNone values are converted to false implicitly
    
    
    Run