Add support for arraybuffer requests in browser

lib/adapters/xhr.js

@@ -36,7 +36,7 @@ module.exports = function xhrAdapter(resolve, reject, config) {
       var headers = parseHeaders(request.getAllResponseHeaders());
       var response = {
         data: transformData(
-          request.responseText,
+          ['text', ''].indexOf(config.responseType || '') !== -1 ? request.responseText : request.response,
           headers,
           config.transformResponse
         ),
@@ -97,4 +97,4 @@ module.exports = function xhrAdapter(resolve, reject, config) {
 
   // Send the request
   request.send(data);
-};
+};