Handling changes in cURL 7.10

In cURL 7.10 and above CURLOPT_SSL_VERIFYPEER is true by default. It
makes library not working without certificates (you can get them here:
http://curl.haxx.se/docs/caextract.html).
Yes, I think we should. Actually, it was what I proposed from the very beginning. )
And I think we should also add note in README about "false by default", so people could understand, that they can use this library without certificate on their own risk. 

BTW, thanks for your work )