Finished list and add commands:

* Moved hosts parsing to base Flatline\Command\Command

* Added hostExists on Flatline\Command\Command
  User on 'add' comand and will be used on 'toggle' command as well

* Added showBlock on Flatline\Command\Command to show colored block messages

* Add command can add disabled (commented out) hosts

* List command can filter hosts by ip, regex and enabled/disabled only