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).
Updating Readme with note about cURL 7.10
Improving handling of CURLOPT_SSL_VERIFYPEER
Merge pull request #5 from chekalskiy/master

Handling changes in cURL 7.10