Fix status

#612
```ruby
> driver.send(:bridge).status
get 
=> #<Selenium::WebDriver::Remote::Response:0x007fbaccaf4ab8
 @code=200,
 @payload=
  {"status"=>0,
   "value"=>{"build"=>{"version"=>"0.5.2"}},
   "sessionId"=>"eeb61d13-40c0-48a2-ba9e-7a9f527aed36"}>
```

There's a different issue where the Ruby bindings can't call status. I'm preparing a patch for upstream.