Fixing incorrect headers join.

Multiple headers were joined by comma which is unacceptable for
`Set-Cookie`. Now multiple headers are returned as array.
Fixes #465

lib/helpers/parseHeaders.js

@@ -29,7 +29,15 @@ module.exports = function parseHeaders(headers) {
     val = utils.trim(line.substr(i + 1));
 
     if (key) {
-      parsed[key] = parsed[key] ? parsed[key] + ', ' + val : val;
+      if (parsed[key]) {
+        parsed[key] = utils.isArray(parsed[key])
+          // third+ value with that key
+          ? parsed[key].concat(val)
+          // second value with that key
+          : [parsed[key]].concat(val);
+      } else {
+        parsed[key] = val;
+      }
     }
   });
 

test/specs/helpers/parseHeaders.spec.js

@@ -7,13 +7,21 @@ describe('helpers::parseHeaders', function () {
       'Date: ' + date.toISOString() + '\n' +
       'Content-Type: application/json\n' +
       'Connection: keep-alive\n' +
-      'Transfer-Encoding: chunked'
+      'Transfer-Encoding: chunked\n' +
+      'Set-Cookie: cookie_key_1=yyy; Path=/\n' +
+      'Set-Cookie: cookie_key_2=xxx; expires=Mon, 17-Oct-2016 17:16:25 GMT; httponly; Max-Age=1209600; Path=/\n' +
+      'Set-Cookie: cookie_key_3=zzz; Path=/www'
     );
 
     expect(parsed['date']).toEqual(date.toISOString());
     expect(parsed['content-type']).toEqual('application/json');
     expect(parsed['connection']).toEqual('keep-alive');
     expect(parsed['transfer-encoding']).toEqual('chunked');
+    expect(parsed['set-cookie']).toEqual([
+      'cookie_key_1=yyy; Path=/',
+      'cookie_key_2=xxx; expires=Mon, 17-Oct-2016 17:16:25 GMT; httponly; Max-Age=1209600; Path=/',
+      'cookie_key_3=zzz; Path=/www'
+    ]);
   });
 });