Updated setup instructions with Windows stack script

1. Added instructions from, and link to, the python script of main software bootcamp repo for Windows installation (initially recommended by @benwaugh).  This addresses the concerns of @jamespjh as Git, Python (together with distribute, pip, nose and test.py) and nano, a text editor are all accessible from Git Bash, installed with msysgit.
2. The second concern of @jamespjh i.e. that eggs will not compile I have tested with my own Windows and OSX setups.  Windows worked fine using easy_install with the setup included in the bootcamp stack.  My OSX stack also worked fine (although I do have XCode command line tools installed).  Someone else will need to check this as I am now off until the 3rd April.