Allow for CURL options to be set, and expose errors

[oligriffiths]

Hi Michael, hope you're well.

Here's a patch to allow setting of CURL options and exposing curl errors. We are investigating some errors with this library hanging indefinitely. I believe this to be due to no CURL timeouts being set, but not totally sure.

This patch will allow us to set whatever CURL options we want, including CURLOPT_CONNECTTIMEOUT and CURLOPT_TIMEOUT.

I also noticed that there doesn't appear to be and handling for if curl responds with an error, but I will leave that update to a future patch as this change will unblock me now and I am unsure how you might like to handle curl errors.