* Elaborates on default values of some curl_easy_setopt() options.
* Reminds the user to cast variadic arguments to curl_easy_setopt() to
'void *' where curl internally interprets them as such.
* Clarifies the working of the CURLOPT_SEEKFUNCTION option for
curl_easy_setopt().
* Fixes typo 'forth' → 'fourth'.
* Elaborates on CURL_SOCKET_TIMEOUT.
* Adds some missing periods.
* Notes that the return value of curl_version() must not be passed to
free().
simply check for CURLM_CALL_MULTI_PERFORM internally. This has the added
benefit that this goes in line with my long-term wishes to get rid of the
CURLM_CALL_MULTI_PERFORM all together from the public API.
