message: Implement robot stop
diff: @@ -300,8 +300,9 @@ class Robot(object):
  Parameters
  ----------
  - axis : str
  + mount : str
  Specifies which axis the instruments is attached to.
  + Valid options are "left" or "right".
  instrument : Instrument
  An instance of a :class:`Pipette` to attached to the axis.
  @@ -312,7 +313,7 @@ class Robot(object):
  ::
  from opentrons.instruments.pipette import Pipette
  - p200 = Pipette(axis='a')
  + p200 = Pipette(mount='left')
  This will create a pipette and call :func:`add_instrument`
  to attach the instrument.
  @@ -798,7 +799,8 @@ class Robot(object):
  """
  Stops execution of the protocol.
  """
  - raise NotImplementedError
  + self._driver.pause()
  + self.reset()
  def resume(self):
  """
  @@ -810,6 +812,7 @@ class Robot(object):
  """
  Stops execution of both the protocol and the Smoothie board immediately
  """
  + # TODO (ben 20171116): make smoothie actions interruptable (no M400)
  raise NotImplementedError
  def get_serial_ports_list(self):
  