Allow to specify client options and colour

Hi, this small 2 patches allow you to pass options to the underlaying ```HipChat::Client``` and to select wich colour to use for the message.

```ruby

  config.middleware.use "HipchatExceptionNotifier",
                        token: " ... your token ....",
                        room_name: "...room id...",
                        user: "Username",
                        options: {
                          api_version: 'v2'
                        },
                        announce: false,
                        color: 'red'
```