echo Test 1.  Should print 2116496681 101484
./pamflip -lr ../testimg.ppm | cksum 
echo Test 2.  Should print 217037000 101484
./pamflip -cw ../testimg.ppm | cksum
echo Test 3.  Should print 2052917888 101484
./pamflip -tb ../testimg.ppm | cksum
echo Test 4.  Should print 3375384165 41
./pamflip -lr ../testgrid.pbm | cksum
echo Test 5.  Should print 604323149 41
./pamflip -tb ../testgrid.pbm | cksum
echo Test 6.  Should print 490797850 37
./pamflip -cw ../testgrid.pbm | cksum