Added SerialPassthrough sketch to communication examples

build/shared/examples/04.Communication/SerialPassthrough/SerialPassthrough.ino

@@ -0,0 +1,39 @@
+/*
+  SerialPassthrough sketch
+
+  Some boards, like the Arduino 101, the MKR1000, Zero, or the Micro,
+  have one hardware serial port attached to Digital pins 0-1, and a
+  separate USB serial port attached to the IDE Serial Monitor.
+  This means that the "serial passthrough" which is possible with
+  the Arduino UNO (commonly used to interact with devices/shields that
+  require configuration via serial AT commands) will not work by default.
+
+  This sketch allows you to  emulate the serial passthrough behaviour.
+  Any text you type in the IDE Serial monitor will be written
+  out to the serial port on Digital pins 0 and 1, and vice-versa.
+
+  On the 101, MKR1000, Zero, and Micro, "Serial" refers to the USB Serial port
+  attached to the Serial Monitor, and "Serial1" refers to the hardware
+  serial port attached to pins 0 and 1. This sketch will emulate Serial passthrough
+  using those two Serial ports on the boards mentioned above,
+  but you can change these names to connect any two serial ports on a board
+  that has multiple ports.
+
+   Created 23 May 2016
+   by Erik Nyquist
+*/
+
+void setup() {
+  Serial.begin(9600);
+  Serial1.begin(9600);
+}
+
+void loop() {
+  if (Serial.available()) {      // If anything comes in Serial (USB),
+    Serial1.write(Serial.read());   // read it and send it out Serial1 (pins 0 & 1)
+  }
+
+  if (Serial1.available()) {     // If anything comes in Serial1 (pins 0 & 1)
+    Serial.write(Serial1.read());   // read it and send it out Serial (USB)
+  }
+}