TodoTxtJs fix sort

TodoTxtJs.TodoManager._compareDueDate = function (left, right) {
if (left.dueDate() || right.dueDate()) {
                if (!left.dueDate())
                    return 1;
                if (!right.dueDate())
                    return -1;
                if (left.dueDate().getFullYear() !== right.dueDate().getFullYear()
                    || left.dueDate().getMonth() !== right.dueDate().getMonth()
                    || left.dueDate().getDay() !== right.dueDate().getDay()) {
                    return left.dueDate() < right.dueDate() ? -1 : 1;
                }
           }
            return 0;
        }