use `compile` to compile command argument string.
refactory importing.
move `compile` function from option.ls to cmd.ls.
enhance compile function for options handling.
simpfied Cmd.$command.
add Cmd.$opts to manuplate options.

- remove option(s) is not implemented.
reorder src/mode.ls.
let Cmd can recive option style setting.
remove unused kwargs instance variable of Cmd.