remove old out-of-date how-it-works.md
remove old out-of-date how-it-works.md

hughperkins/cuda-on-cl,hughperkins/coriander,hughperkins/cuda-on-cl,hughperkins/coriander,hughperkins/cuda-on-cl,hughperkins/coriander,hughperkins/coriander,hughperkins/cuda-on-cl