in BiColorLED.h please change
#include "WProgram.h"
to
#if defined(ARDUINO) && ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif
For Arduino 1.x support
And to help PaulS and anyone else Doc lost, you must look at the current from the viewpoint of the Bi-Polar LED pair, not the Arduino. To the the Arduino, it's just DC, BUT to the pair of diodes being driven by the Arduino, it's A/C.