pybricks.common.Motor: Make angle reset optional.

This adds a reset_angle=True keyword argument to the Motor class initialization.

Setting it to false allows the encoder offset to be preserved between consecutive scripts. This way, you'd need to reset robot mechanisms only once instead of every time you run a program.

pybricks/support#389

pybricks/common/pb_type_motor.c

@@ -34,11 +34,13 @@ STATIC mp_obj_t common_Motor_make_new(const mp_obj_type_t *type, size_t n_args,
     PB_PARSE_ARGS_CLASS(n_args, n_kw, args,
         PB_ARG_REQUIRED(port),
         PB_ARG_DEFAULT_OBJ(positive_direction, pb_Direction_CLOCKWISE_obj),
-        PB_ARG_DEFAULT_NONE(gears));
+        PB_ARG_DEFAULT_NONE(gears),
+        PB_ARG_DEFAULT_TRUE(reset_angle));
 
     // Configure the motor with the selected arguments at pbio level
     pbio_port_id_t port = pb_type_enum_get_value(port_in, &pb_enum_type_Port);
     pbio_direction_t positive_direction = pb_type_enum_get_value(positive_direction_in, &pb_enum_type_Direction);
+    bool reset_angle = mp_obj_is_true(reset_angle_in);
     pbio_error_t err;
     pbio_servo_t *srv;
 
@@ -82,7 +84,7 @@ STATIC mp_obj_t common_Motor_make_new(const mp_obj_type_t *type, size_t n_args,
     pb_assert(pbio_motor_process_get_servo(port, &srv));
 
     // Set up servo
-    while ((err = pbio_servo_setup(srv, positive_direction, gear_ratio)) == PBIO_ERROR_AGAIN) {
+    while ((err = pbio_servo_setup(srv, positive_direction, gear_ratio, reset_angle)) == PBIO_ERROR_AGAIN) {
         mp_hal_delay_ms(1000);
     }
     pb_assert(err);