* Added request options:

* Added request options:
 - postredir: enforcing RFC conformig POST after redirect (libcurl >= 7.17.1)
 - address_scope: RFC4007 zone_id (libcurl >= 7.19.0)
 - ssl->issuercert: validate peer certificate issuer (libcurl >= 7.19.0)
 - ssl->crlfile: require CRL check (libcurl >= 7.19.0 with openssl)
 - ssl->certinfo: enable the certinfo gatherer (libcurl >= 7.19.1 with openssl)
* Added proxytype request option constants:
 - HTTP_PROXY_SOCKS4A
 - HTTP_PROXY_SOCKS5_HOSTNAME
* Added request info members:
 - redirect_url (libcurl >= 7.18.2)
 - primary_ip (libcurl >= 7.19.0)
 - appconnect_time (libcurl >= 7.19.0)
 - certinfo (libcurl >= 7.19.1 with openssl)