Previous implementation was using its own refcounting (uses field of
the php_curl struct). zend_list_add/remove already implements its own
refcount, so we don't need to use an other one.

CURLOPT_PASSWDFUNCTION was removed in cURL 7.15.5, the passwd field
will not be used for version greater than this one

Addes new curl options CURLOPT_TELNETOPTIONS, CURLOPT_GSSAPI_DELEGATION,
CURLOPT_ACCEPTTIMEOUT_MS, CURLOPT_SSL_OPTIONS, CURLOPT_TCP_KEEPALIVE,
CURLOPT_TCP_KEEPIDLE and CURLOPT_TCP_KEEPINTVL.

* PHP-5.4:
  Fixed #63859 Memory leak when reusing curl-handle

When CURLOPT_POSTFIELDS is called more than once on the same
curl handle, php/curl did not free the memory of the previous
post data. This commit will fix the problem unless the curl
handle was previously duplicated using the curl_copy_handle()
function in which case we can not know if the post data is
still in use or not by any curl handle

Thanks Laruence :)

Add the curl_pause function (binding of curl_easy_pause).
Using this function, you can explicitly mark a running connection
to get paused, and you can unpause a connection that was
previously paused.

Add the support for both curl_strerror and curl_multi_strerror.
Those function will return a string describing the error code
passed in the argument errornum

curl_multi_setopt is now available and supports CURLMOPT_PIPELINING
and CURLMOPT_MAXCONNECTS