mv bittrex dep to GB, update version

exchange/package.json

@@ -31,6 +31,7 @@
     "moment": "^2.22.1",
     "poloniex.js": "git://github.com/askmike/poloniex.js.git#69f5e254353e66d135070844fc3328efcbe3641c",
     "request-promise": "^4.2.2",
-    "retry": "^0.12.0"
+    "retry": "^0.12.0",
+    "node.bittrex.api": "^1.0.0"
   }
 }

exchange/wrappers/bittrex.js

@@ -1,24 +1,21 @@
-var Bittrex = require('node.bittrex.api');
-var util = require('../core/util.js');
-var _ = require('lodash');
-var moment = require('moment');
-var log = require('../core/log');
+const Bittrex = require('node.bittrex.api');
+const _ = require('lodash');
+const moment = require('moment');
 
 // Helper methods
 function joinCurrencies(currencyA, currencyB){
     return currencyA + '-' + currencyB;
 }
 
 var Trader = function(config) {
-  _.bindAll(this);
-
   if(!config.key) {
-    // no api key defined -> we need to set a dummy key, otherwise the Bittrex module will not work even for public requests
+    // no api key defined -> we need to set a
+    // dummy key, otherwise the Bittrex module
+    // will not work even for public requests.
     config.key = 'dummyApiKey';
     config.secret = 'dummyApiKey';
   }
 
-  // override if cmd line mode (not --ui)
   if(_.isObject(config)) {
     this.key = config.key;
     this.secret = config.secret;

package.json

@@ -41,7 +41,6 @@
     "lodash": "2.x",
     "moment": "^2.20.1",
     "node-wex": "^1.0.3",
-    "node.bittrex.api": "^0.4.3",
     "okcoin-china": "0.0.7",
     "opn": "^4.0.2",
     "promisify-node": "^0.4.0",