Ui improvement

implemented a new number select view on the alert dialog appeared in changing a value of blocks

in accordance of this implementation, the old 'SelectNumberView' has been changed so that
it inherits a common new parent class named 'NumberSelectView'
SelectNumberViewだとこのViewの中身を表せていないので，
NumberPickerView？
上のと合わせるとしたらNumberSelectPickerView（SelectとPickerで被るなぁ）？NumberSelectScrollViewとか？