Spins Incorporated

I have tried to incorporate the spin parameters (spin1z, spin2z), within the range -0.1 to 0.1. I have not made any changes to the plotting code in "plot-bank.py" so that it will show a plot between mass1 and mass2, even though each sampled point now has 4 parameters, i.e., mass1, mass2, spin1z and spin2z. I am going to run some tests once the changes are approved and I have not overlooked any function that should be modified!