examples: add microbit blink example

Signed-off-by: Ron Evans <ron@hybridgroup.com>

src/examples/microbit-blink/microbit-blink.go

@@ -0,0 +1,19 @@
+// blink program for the BBC micro:bit that uses the entire LED matrix
+package main
+
+import (
+	"machine"
+	"time"
+)
+
+func main() {
+	machine.InitLEDMatrix()
+
+	for {
+		machine.ClearLEDMatrix()
+		time.Sleep(time.Millisecond * 500)
+
+		machine.SetEntireLEDMatrixOn()
+		time.Sleep(time.Millisecond * 500)
+	}
+}