add M0

added M0 w/ adafruit feather dev board with index.hml, and updated json

gpio/m0/m0_arduino/m0_arduino.ino

+void setup() {
+  // put your setup code here, to run once:
+  pinMode(10, OUTPUT);
+  pinMode(11, INPUT);
+
+}
+
+void loop() {
+  while (1) {
+    digitalWrite(10, 1 - digitalRead(11));
+  }
+}