Documentation examples of SSL config options; closes #116

> You don't need to use `RCurl::curlOptions` at all - just feed the args directly to `config()`

Ok, I'll take them out.  I slightly prefer the `curlOptions` because it adds a little more structure.  But I'm happy to make simplify it.  I'll submit another commit in a minute.

> Also is there a reason that httr shouldn't just default to `sslversion = 3`?

I don't have any objections.  But I'm far from a web developer and have very little feel how most servers are configured and how clients typically use cURL. I'm also wondering if there's a reason the Linux version of cURL all of sudden doesn't default to it.