Add Exbitron API to price feeds. Other minor changes

lib/market.js

@@ -137,6 +137,33 @@ function getExchangeMarkets (exchange, callback) {
 			callback(null, data);
 		}, '/v1/ticker');
 	}
+// Exbitron
+else if (exchange == "exbitron") {
+    apiInterfaces.jsonHttpRequest('api.exbitron.digital', 443, '', function (error, response) {
+        if (error) log('error', logSystem, 'API request to %s has failed: %s', [exchange, error]);
+
+        let data = {};
+        if (!error && response && response.status === "OK" && response.data) {
+            let market = response.data.market;
+            let pairParts = market.id.split('-');
+            let symbol = pairParts[0];
+            let target = pairParts[1];
+
+            let price = +market.marketDynamics.lastPrice;
+            if (price !== 0) {
+                if (!data[symbol]) data[symbol] = {};
+                data[symbol][target] = price;
+            }
+        }
+
+        if (!error) marketRequestsCache[cacheKey] = {
+            ts: currentTimestamp,
+            data: data
+        };
+        callback(null, data);
+    }, '/api/v1/trading/info/' + config.symbol + '-USDT');
+}
+
 
 	// Crex24
 	else if (exchange == "crex24") {