JSON status to simplify automatic monitoring

Hi,

we modified the the status resource to return json instead of a HTML table. This can be used to simplify monitoring. Example output looks like this:

```
{
  upstream_servers: 4,
  generation: 1,
  peers: [
    {
      upstream: "example-api.com",
      member: "192.168.1.1:80",
      status: "up",
      rise_count: 8,
      fall_count: 0,
      check_type: "http"
    },
    {
      upstream: "www.example-app.com",
      member: "192.168.1.2:80",
      status: "up",
      rise_count: 8,
      fall_count: 0,
      check_type: "http"
    },
    {
      upstream: "www.company.com",
      member: "192.168.1.3:80",
      status: "up",
      rise_count: 9,
      fall_count: 0,
      check_type: "http"
    },
  ]
}
```

There is lot's of room for improvement regarding the structure of the hash but i still hope you like the idea.

Cheers!
Daniel