added test check_dir_re() for regexp searching; improved check_dir() test; added check_dir_noargs(); issue 14
added test check_dir_re() for regexp searching; improved check_dir() test; added check_dir_noargs(); issue 14

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