[fix] Allow close codes 1012 and 1013

IANA has them assigned as "Service Restart", and "Try Again Later",
respectively.

http://www.iana.org/assignments/websocket/websocket.xhtml#close-code-number
https://developer.mozilla.org/en-US/docs/Web/API/CloseEvent

lib/ErrorCodes.js

@@ -8,7 +8,7 @@
 
 module.exports = {
   isValidErrorCode: function (code) {
-    return (code >= 1000 && code <= 1011 && code !== 1004 && code !== 1005 && code !== 1006) ||
+    return (code >= 1000 && code <= 1013 && code !== 1004 && code !== 1005 && code !== 1006) ||
       (code >= 3000 && code <= 4999);
   },
   1000: 'normal',
@@ -22,5 +22,7 @@ module.exports = {
   1008: 'policy violation',
   1009: 'message too big',
   1010: 'extension handshake missing',
-  1011: 'an unexpected condition prevented the request from being fulfilled'
+  1011: 'an unexpected condition prevented the request from being fulfilled',
+  1012: 'service restart',
+  1013: 'try again later'
 };

test/WebSocket.test.js

@@ -1538,6 +1538,20 @@ describe('WebSocket', function() {
         });
       });
     });
+
+    it('allows close code 1013', function (done) {
+      var wss = new WebSocketServer({port: ++port}, function () {
+        var ws = new WebSocket(`ws://localhost:${port}`);
+        ws.on('close', function (code) {
+          assert.strictEqual(code, 1013);
+          wss.close(done);
+        });
+      });
+
+      wss.on('connection', function (ws) {
+        ws.close(1013);
+      });
+    });
   });
 
   describe('W3C API emulation', function() {