Improvements to new OBT process tutorial

@AlbertoElias could you review this, and also step through the tutorial on a completely blank VM to check that it all works.  I suggest you use Cloud9 to do this:

http://c9.io

Choose a 'custom' VM, and do exactly what is in the tutorial to make sure it works.  The reason to use C9 is that Windows users coming to the workshop might well use it.