updated SPI API & impl to match current WiringPi version

Makefile

@@ -0,0 +1,22 @@
+clean:
+	make -C wiringPi clean
+	make -C devLib clean
+	make -C gpio clean
+	make -C examples clean
+	make -C examples/Gertboard clean
+	make -C examples/PiFace clean
+	make -C examples/q2w clean
+	make -C examples/PiGlow clean
+
+install:
+	make -C wiringPi
+	make -C wiringPi install
+	make -C devLib
+	make -C devLib install
+	make -C gpio
+	make -C gpio install
+	mkdir -p /usr/share/wiringPi/examples/Gertboard
+	mkdir -p /usr/share/wiringPi/examples/PiFace
+	mkdir -p /usr/share/wiringPi/examples/PiGlow
+	mkdir -p /usr/share/wiringPi/examples/q2w
+	find examples -exec install -m 0644 -D -t /usr/share/wiringPi/examples {} \;