Doesn't work with default Arduino Blink Sketch because of LED Pin definitions

[gppk]

in pins_arduino.h for every variant the following line is included:

#define LED D13

If you also add the following line then the redbear boards will compile out of the box with the Arduino blink sketch.

#define LED_BUILTIN D13

[gppk]

I have created a pull request #105 which fixes this issue