*) changed travelling row bit to travelling column bit to eliminate this
nasty flickering:

http://forum.arduino.cc/index.php?topic=204377
https://www.youtube.com/watch?v=ivCGI88enM8
+) arduino/Makefile --- ISP definitions
+) ULN2803 on hardware side to not overstress on a walking column
*) the code in arduino/binary_clock.ino is changed to account for the
ULN