add current cycle phase index, number of attachments, and number of spring attachments to signals#381

drbergman wants to merge 4 commits intoMathCancer:developmentMathCancer/PhysiCell:developmentfrom

drbergman:feature-cycle-phase-index-as-signaldrbergman/PhysiCell:feature-cycle-phase-index-as-signalCopy head branch name to clipboard