Event Handling

Hi Ravi. Pushed a start for tor event handling to the 'events' branch of my repository...

https://gitweb.torproject.org/user/atagar/stem.git/shortlog/refs/heads/events

Usage is pretty simple. The following for instance would print the bytes sent and received by tor for five seconds...

import time
from stem.control import Controller, EventType

def print_bw(event):
  print "sent: %i, received: %i" % (event.written, event.read)

with Controller.from_port(control_port = 9051) as controller:
  controller.authenticate()
  controller.add_event_listener(print_bw, EventType.BW)
  time.sleep(5)

Cheers! -Damian