changed code in firmware for pose (s -> z)

Author: gbr1

examples/firmware_01/firmware_01.ino

@@ -218,7 +218,7 @@ void loop(){
     msg_size = packeter.packetC2F('v', alvik.getLinearVelocity(), alvik.getAngularVelocity());
     alvik.serial->write(packeter.msg, msg_size);
     // pose
-    msg_size = packeter.packetC3F('s', alvik.getX(), alvik.getY(), alvik.getTheta());
+    msg_size = packeter.packetC3F('z', alvik.getX(), alvik.getY(), alvik.getTheta());
     alvik.serial->write(packeter.msg, msg_size);
 
     if (alvik.getKinematicsMovement()!=MOVEMENT_DISABLED){