Short version: the previous version of `get_raw` would return the raw response body regardless of whether the request succeeded or failed. Considering an error would usually be an HTML 404 page, I figured this wasn’t actually the intended behaviour, so I made it as consistent as I could (returning `nil` rather than raising an exception) while still doing something sensible.

The initial implementation, which was for returning KML files from Imminence, was written by @jystewart, so he may have some more information on how this was initially supposed to work. As an extra bit of context, I don’t believe we have anything that uses this code any more, so it might well be we can remove it in the next major version.