spins added and hull usage removed

I have added the spin parameters (spin1z and spin2z) within the range -0.1 to 0.1. I have not run any tests since it would be better to have the code reviewed by you first. This fresh PR includes both the spin incorporation and removal of the hull sampling code. Also, don't worry about the indentations, I have checked those and corrected them. I'll run some tests as soon as the code is reviewed.