minimize rest requests...

    ticker:function(pair, cb){

        const time = new Date().getTime();
        if (time - lastTickerTime > 2000 ) {

            // console.log("Get Ticker" + pair);
            if (logAllApiCalls){
                console.log(apiCallsCount + " ticker.binance.prices: " + pair + " - " + Date.now());
                apiCallsCount += 1;
            }
            binance.prices(pair, (error, ticker) => {

                if (error) {
                    console.log(pair);
                    console.log(chalk.red("binance.ticker error: " + error.body));
                    cb(false);
                }
                else {
                    lastTickerTime = new Date().getTime();
                    lastTicker = ticker[pair];
                    cb(ticker[pair]);
                }
            });
        }
        else {
            // console.log("Using cached ticker");
            cb(lastTicker);
        }
    },