making cli options unixy

now all cli options are unix style. 

This still leaves us with one problem. If you provide a cli option --abc, methadone converts it to ```{:abc => true, "abc" => true}```. 
Only for cli options starting with 'no', it returns a false value. e.g ```--no-power-on => {:"no-power-on" => false, "no-power-on" => false}```. This sounds wrong. This PR does not address this problem. 


@annashipman : pls take a look.