Merge branch 'odewdney-arduino-usb-bootloader-discovery'

Pulling in changes for new IDE 1.6.9 bootloader check.

Author: Brent Wilkins

sparkfun/avr/variants/promicro/pins_arduino.h

@@ -366,4 +366,15 @@ const uint8_t PROGMEM analog_pin_to_channel_PGM[] = {
 // Alias SerialUSB to Serial
 #define SerialUSB SERIAL_PORT_USBVIRTUAL
 
+#ifndef MAGIC_KEY
+#define MAGIC_KEY 0x7777
+#endif
+
+#ifndef MAGIC_KEY_POS
+#define MAGIC_KEY_POS 0x0800
+#endif
+#ifndef NEW_LUFA_SIGNATURE
+#define NEW_LUFA_SIGNATURE 0xDCFB
+#endif
+
 #endif /* Pins_Arduino_h */