When adding options to a path, don't drop existing keys. This will enable image pagination when there is a type key to work. The bug was trying to addOptions to an existing path with query values. Previously if a path `/path?type=alpha` was passed, key `page=2` would be appeneded, but `type=alpha` would be dropped.
This makes it possible for consumers of the package to debug API calls made to the DO APIs.
Usage:
client.OnRequestCompleted(func(req *http.Request, resp *http.Response) {
// ... e.g. use httputil.DumpRequest / httputil.DumpResponse
})
bryanl