message: Use enviornment variable for robot config
diff: # once this configuration information is part of persistent robot data
  from collections import namedtuple
  +import os
  PLUNGER_CURRENT_LOW = 0.1
  PLUNGER_CURRENT_HIGH = 0.5
  -CURRENT_ROBOT = 'B2-5'
  +current_robot = os.environ['OT_ROBOT_CONFIG']
  robot_config = namedtuple(
  'robot_config',
  @@ -127,4 +128,4 @@ robots = {
  }
  -config = robots[CURRENT_ROBOT]
  +config = robots[current_robot]
  