Reconnect is broken

See [here](https://github.com/foreverjs/nssocket/blob/master/lib/nssocket.js#L305).

```
// Attempts to reconnect the current socket on `close` or `error`.
```

Yes, This is true. It tries to reconnect 2 times: 1 reconnect call from `_onError` and second from `_onClose`. `NsSocket.prototype.reconnect` is not guarded for multiple reconnects.
