examples: add hello world serial communication

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

src/examples/serial/serial.go

@@ -0,0 +1,10 @@
+package main
+
+import "time"
+
+func main() {
+	for {
+		println("hello world!")
+		time.Sleep(time.Second)
+	}
+}