Minor error

https://github.com/qoobaa/s3/blob/386361c1b0ede19cde0ddaf86e41a16308575f5d/lib/s3/connection.rb#L67

Should be:

```
    if params.present?
      params = params.is_a?(String) ? params : self.class.parse_params(params)
      path << "?#{params}"
    end
```

Because it adds a "?" on every request.
