Allow http(s) options pass through

Pass generic http(s) request options through to the underlying request
call as detailed here
http://nodejs.org/docs/latest/api/https.html#https_https_request_options_callback.

This is useful in a specific case as https requests to remote endpoints with invalid or self-signed certs are appropriately failed by default as of node v0.9.x (12?).  In order to make requests to self-signed cert endpoints you must pass `{ rejectUnauthorized: true }` to the underlying `https.request` function.  This allows for that, as well as any other arbitrary options values to flow through.