added some notes about https://bitbucket.org/birkenfeld/ipython-physics/
added some notes about https://bitbucket.org/birkenfeld/ipython-physics/

jamiebull1/eppy,pachi/eppy,eayoungs/eppy,pachi/eppy,eayoungs/eppy,jamiebull1/eppy,santoshphilip/eppy,jamiebull1/eppy,santoshphilip/eppy,santoshphilip/eppy,eayoungs/eppy,pachi/eppy