Move some JSON to fixtures_test.
Add IPAddresses to server fetch.

These are pretty different than the PublicIPAddress stuff and probably
can't/shouldn't share a struct.
Don't export CLCRequestor.
Include error messages in RequestError if available.

Depending on how much we want to hold people's hands with default vaules
and such, this might be all we need. Read the docs, use the error
messages to change your submission.