List directory contents with common filters and sort orders.

    There are a thousand ways to replace 'ls' and all of its cryptic
    parameters with a 'dir' command.  Hopefully this is the best one you
    will ever encounter.  :-)

Usage: dir <action:*> # Where action is:

    dir   List the directories in this directory.
    help  Help by showing these instructions.
    size  List from smallest to largest.
    time  List from oldest to newest.
    *     <glob>  Show directory listing for <glob>.  [default]