Updated visibility from private to protected
Added extra option to configure HTTP authentication
Added method to tweak HTTP headers of request
Merge pull request #31 from mremi/http-auth

Added extra option to configure HTTP authentication
Removed reference to return an array of HTTP headers
Merge pull request #32 from mremi/filter-request-headers

Added method to tweak HTTP headers of request
Update Curl class to support CURLOPT_CAINFO and CURLOPT_CAPATH options