Fixing issue with multibyte characters in node

closes #38

lib/adapters/http.js

@@ -52,15 +52,15 @@ module.exports = function httpAdapter(resolve, reject, config) {
   // Create the request
   var transport = parsed.protocol === 'https:' ? https : http;
   var req = transport.request(options, function (res) {
-    var responseText = '';
+    var responseBuffer = [];
     res.on('data', function (chunk) {
-      responseText += chunk;
+      responseBuffer.push(chunk);
     });
 
     res.on('end', function () {
       var response = {
         data: transformData(
-          responseText,
+          Buffer.concat(responseBuffer).toString('utf8'),
           res.headers,
           config.transformResponse
         ),

test/unit/axios/http.js

@@ -0,0 +1,44 @@
+var axios = require('../../../index');
+var http = require('http');
+var server;
+
+module.exports = {
+  tearDown: function (callback) {
+    server.close();
+    server = null;
+    callback();
+  },
+
+  testJSON: function (test) {
+    console.log('testJSON');
+    var data = {
+      firstName: 'Fred',
+      lastName: 'Flintstone',
+      emailAddr: 'fred@example.com'
+    };
+
+    server = http.createServer(function (req, res) {
+      res.setHeader('Content-Type', 'application/json;charset=utf-8');
+      res.end(JSON.stringify(data));
+    }).listen(4444, function () {
+      axios.get('http://localhost:4444/').then(function (res) {
+        test.deepEqual(res.data, data);
+        test.done();
+      });
+    });
+  },
+
+  testUTF8: function (test) {
+    var str = Array(100000).join('ж');
+
+    server = http.createServer(function (req, res) {
+      res.setHeader('Content-Type', 'text/html; charset=UTF-8');
+      res.end(str);
+    }).listen(4444, function () {
+      axios.get('http://localhost:4444/').then(function (res) {
+        test.equal(res.data, str);
+        test.done();
+      });
+    });
+  }
+};