title: Running multiple devices with calabash ios
body: <p>Have been searching for a workaround to run multiple devices with calabash ios. 
  AFAIK, calabash ios uses port 37265 and instrument to load and interact with the app.
  Instrument can also only run once at a time. I have read somewhere that we might need to use virtual machine, is that true? Is there any other way to achieve this? Thanks a bunch.</p>