Added logic to allow graceful shutdown of Tmux from CLI. This is useful ...

Added logic to allow graceful shutdown of Tmux from CLI. This is useful for such things as scheduling a stop / start with Crontab on reboot. One function was added to controllers/Tmux.php to set the active bit within the database to true. Stop.php will start the Tmux shutdown process by setting the active bit to false. Run will call the new function setting it to true.
An alternative is to return line 457 as a boolean.