Add print statements to battery and led

micropython/modules/opencube_brick/battery.c

@@ -34,7 +34,8 @@ bool read_voltage_handler(repeating_timer_t *timer) {
 }
 
 static void battery_print(const mp_print_t *print, mp_obj_t self_in) {
-    //battery_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    battery_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_printf(print, "Battery last value: %f V", self->last_value);
 }
 
 static mp_obj_t battery_read_voltage(mp_obj_t self_in) {

micropython/modules/opencube_brick/led.c

@@ -29,7 +29,7 @@ static mp_obj_t led_make_new(const mp_obj_type_t* type, size_t n_args, size_t n_
 }
 
 static void led_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
-  mp_printf(print, "Led");
+  mp_printf(print, "Open-Cube user LED");
 }
 
 static mp_obj_t led_on(mp_obj_t self_in) {