moving pathlist to mapping.py, and moving comments into new subclasses from mapping.py
moving pathlist to mapping.py, and moving comments into new subclasses from mapping.py

cjlee112/pygr,RitwikGupta/pygr,cjlee112/pygr,ctb/pygr,ctb/pygr,theoryno3/pygr,ctb/pygr,GenDataPro/pygr,RitwikGupta/pygr,theoryno3/pygr,theoryno3/pygr,cjlee112/pygr,GenDataPro/pygr,cjlee112/pygr,RitwikGupta/pygr,ctb/pygr,GenDataPro/pygr,ctb/pygr