Remove module exports in BigInteger.js (Dash-Industry-Forum#4756)

Author: dsilhavy

externals/BigInteger.js

@@ -1280,9 +1280,7 @@ var bigInt = function (undefined) {
     };
     return Integer
 }();
-if (typeof module !== 'undefined' && module.hasOwnProperty('exports')) {
-    module.exports = bigInt
-}
+
 if (typeof define === 'function' && define.amd) {
     define('big-integer', [], function () {
         return bigInt