IO: Add comments pointing to wiring diagrams

java/libraries/io/examples/I2CCompass/I2CCompass.pde

@@ -3,6 +3,7 @@ I2C i2c;
 
 // HMC6352 is a digital compass module using I2C
 // datasheet: https://www.sparkfun.com/datasheets/Components/HMC6352.pdf
+// see setup.png in the sketch folder for wiring details
 
 void setup() {
   //printArray(I2C.list());

java/libraries/io/examples/Interrupt/Interrupt.pde

@@ -3,6 +3,7 @@ color bgcolor = 0;
 
 // GPIO numbers refer to different phyiscal pins on various boards
 // On the Raspberry Pi GPIO 4 is physical pin 7 on the header
+// see setup.png in the sketch folder for wiring details
 
 void setup() {
   GPIO.pinMode(4, GPIO.INPUT);

java/libraries/io/examples/SPIAnalogDigital/SPIAnalogDigital.pde

@@ -3,6 +3,7 @@ SPI spi;
 
 // MCP3001 is a Analog-to-Digital converter using SPI
 // datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf
+// see setup.png in the sketch folder for wiring details
 
 void setup() {
   //printArray(SPI.list());

java/libraries/io/examples/SPIAnalogDigitalOOP/SPIAnalogDigitalOOP.pde

@@ -1,6 +1,8 @@
 import processing.io.*;
 MCP3001 adc;
 
+// see setup.png in the sketch folder for wiring details
+
 void setup() {
   //printArray(SPI.list());
   adc = new MCP3001(SPI.list()[0]);

java/libraries/io/examples/SimpleInput/SimpleInput.pde

@@ -2,6 +2,7 @@ import processing.io.*;
 
 // GPIO numbers refer to different phyiscal pins on various boards
 // On the Raspberry Pi GPIO 4 is physical pin 7 on the header
+// see setup.png in the sketch folder for wiring details
 
 void setup() {
   GPIO.pinMode(4, GPIO.INPUT);

java/libraries/io/examples/SimpleOutput/SimpleOutput.pde

@@ -3,6 +3,7 @@ boolean ledOn = false;
 
 // GPIO numbers refer to different phyiscal pins on various boards
 // On the Raspberry Pi GPIO 4 is physical pin 7 on the header
+// see setup.png in the sketch folder for wiring details
 
 void setup() {
   GPIO.pinMode(4, GPIO.OUTPUT);