Create a test server

[tarsisazevedo]

I think it will be good have a official test server to make easier tests with godo.
Today, to test something with godo, we need to start a fake server and mock digitalocean api.

If you guys agree I can implement it and submit a PR. :)

[bryanl]

Hello

Using golang.org/pkg/net/http/httptest/, you could manage your own test server. All responses are documented at https://developers.digitalocean.com/documentation/v2. I'm not sure we'd need to create a test server.