File Distribution

1. I cleaned imports up
1. Added the Private API's File Distribution

We may want to revisit how the request parameters are made. The distribution API has a lot of optional parameters which are not possible in golang. To use the distribution API, you have to do the following.

```
client := new(govt.Client)
client.Apikey = "deadbeefdeadbeef"
client.Url = "https://www.virustotal.com/vtapi/v2/"

dparams := &govt.Parameters{"limit": "10", "reports": "true"}
dresult, _ := client.GetFileDistribution(dparams)
fmt.Print(dresult)
```