Toxics are not set when creating a proxy for the first time.

When using the Go client as follows, toxics are not added to a proxy.
Given `var p []toxiproxy.Proxy` with toxics.

``` Go
proxy := client.NewProxy(&p)
proxy.Create()
```

This does not properly add the configured toxics from `p` onto the proxy.

They must be added after the fact using `Proxy.SetToxic`.
