Close the http.Get() request after opened

[nikolas]

Hound sometimes gives errors like these when it's backed up:

http: Accept error: accept tcp [::]:9999: accept4: too many open files;

I think this can be avoided with the changes here. It's best practice to
close the http.Get() response, and also to use a new instance of
http.Client instead of the http.DefaultClient singleton (used by calls
to http.Get()).

I've given the new http.Client a 2-second timeout, which should be fine,
but we can adjust as needed.

• https://stackoverflow.com/a/48342086/173630
• https://golang.org/pkg/net/http/