Improvements

- Add two config options for conditionally stopping processes:

    - "min_uptime": if a process is restarted with an uptime smaller than this value,
        this restart counts as an unstable restart. If this option is not specified,
        all restarts are considered unstable.

    - "restart_time_limit": if the number of unstable restarts exceeds this number,
        the process will be stopped and a message with number with restarts will be logged.

- Delete corresponding pidFile when a process dies. (https://github.com/Unitech/pm2/issues/44)

- Fixed: `Satan` output to `pm2.log` does not line break properly.