added bsp/board/iot-lab_A8-M3 (blind copy of iot-lab_M3)
added iot-lab_A8-M3 to the build system
iot-lab_A8-M3: sed -i s/iot-lab_M3/iot-lab_A8-M3/g
updated spi.c to match iot-lab_A8-M3 arch