Handle 0-length buffers.

- Work around behavioral differences in different NodeJS versions with respect
  0-length buffers. Explicitly avoid attempting a copy() unless we're going
  to be operating on > 0 bytes.
- Change 'error' event to 'wserror' to avoid EventEmitter throwing an error.

lib/websocket.js

@@ -444,8 +444,13 @@ var WebSocket = function(url, proto) {
                         data = d;
                     } else {
                         var data2 = new buffer.Buffer(data.length + d.length);
-                        data.copy(data2, 0, 0, data.length);
-                        d.copy(data2, data.length, 0, d.length);
+
+                        if (data.length) {
+                            data.copy(data2, 0, 0, data.length);
+                        }
+                        if (data2.length) {
+                            d.copy(data2, data.length, 0, d.length);
+                        }
 
                         data = data2;
                     }
@@ -461,8 +466,23 @@ var WebSocket = function(url, proto) {
                                 'actual=\'' + str2hex(actual) + '\''
                             );
 
-                            self.emit('error', new Error('Invalid handshake from server'));
-                            self.close();
+                            process.nextTick(function() {
+                                // XXX: Emit 'wserror' here, as 'error' is a reserved word in the
+                                //      EventEmitter world, and gets thrown.
+                                self.emit(
+                                    'wserror',
+                                    new Error('Invalid handshake from server:' +
+                                        'expected \'' + str2hex(expected) + '\', ' +
+                                        'actual \'' + str2hex(actual) + '\''
+                                    )
+                                );
+
+                                if (self.onerror) {
+                                    self.onerror();
+                                }
+
+                                self.close();
+                            });
                         }
 
                         // Un-register our data handler and add the one to be used