Refactor the Kucoin test data

[maxima-net]

Like that

export const orderBookCases = {
    default: {
        data: {
            ltc_btc: [
                {
                    type: 'ask',
                    price: 0.01665,
                    amount: 0.06,
                    tid: 200623735,
                    timestamp: 1526172281
                },
                ...
            ]
        },
        expected: <OrderBook>{
            sellOrders: [
                {
                    amount: 0.06,
                    price: 0.01665,
                    orderType: OrderType.Sell,
                    pair: ['ltc', 'btc']
                },
               ...
            ],
            ...
        }
    }
};