Jan 28, 2013 
Upgrade to 1.2

1) Typo: Fixed minor error in equation for evacuation of final shell (will give slightly different results)
2) Adapted to setup.py-based installation 
    a) Added setup.py
    b) Rewrote tests to allow for either installed or unzipped placevent
    c) Uploaded to Pypi (try pip install placevent) 
       
