Add board support for the Arduino YUN ATMEGA32U4 coprocessor.

LUFA/DoxygenPages/ChangeLog.txt

@@ -11,6 +11,7 @@
   *  - Core:
   *   - Updated the BUILD build system module to add a new COMPILER_PATH optional variable
   *   - Added Serial_IsSendReady() and Serial_IsSendComplete() functions to the Serial hardware peripheral driver
+  *   - Added support for the Arduino Yun board (ATMEGA32U4 coprocessor)
   *  - Library Applications:
   *   - Added new Dual MIDI class driver device demo
   *

LUFA/DoxygenPages/DeviceSupport.txt

@@ -98,6 +98,7 @@
  *   - Adafruit U4 Breakout Board
  *   - Arduino Uno
  *   - Arduino Leonardo
+ *   - Arduino Yun
  *   - Bitwizard Multio and Big-Multio
  *   - Busware BUI
  *   - Busware CUL V3