Added support for IRC notifications

I added support for IRC Contacts / Notification.

```ruby
God.watch do |w|
  God.contact(:irc) do |c|
    c.name = 'irc'
    c.host = 'irc.freenode.org'
    c.port = 6667
    c.channel = '#mychannel'
    c.nick = 'its_me_god'
    c.realname = "God"
  end

  w.name = "my_task"
  w.start = "ruby do_random_stuff.rb"
  w.keepalive(:memory_max => 150.megabytes, :cpu_max => 50.percent)
  w.interval = 60.seconds
  w.behavior(:clean_pid_file)

  w.transition(:up, :restart) do |on|
    on.condition(:process_exits) do |c|
      c.notify = 'irc'
    end
  end
end
```