'App::CLI' dispatches CLI (command line interface) based commands into
command classes. It also supports subcommand and per-command options.

get_opt([@config], %opt_map)
give options map, process by Getopt::Long::Parser

interface of dispatcher

cmd_map($cmd)
find package name of subcommand in constant %alias

if it's finded, return ucfirst of the package name,

otherwise, return ucfirst of $cmd itself.

get_cmd($cmd, @arg)
return subcommand of first level via $ARGV[0]