Fix for IE11 issues

Unlike other browsers, IE does not check property values when redefining
non-configurable properties, and simply throws whether they're the same
or not. This sets configurable: true early, since the list overwrites
some of its symbols during construction.

list/list.js

@@ -341,6 +341,7 @@ var eventsProtoSymbols = ("getOwnPropertySymbols" in Object) ?
 
 eventsProtoSymbols.forEach(function(sym) {
   Object.defineProperty(DefineList.prototype, sym, {
+  	configurable: true,
     enumerable:false,
     value: define.eventsProto[sym],
     writable: true