DOCS: Added clarification to CURLOPT_CUSTOMREQUEST for the POP3 protocol

to the particular request method, it will only change the actual string sent

in the request.

For example: if you tell libcurl to do a HEAD request, but then change the

request to a "GET" with \fBCURLOPT_CUSTOMREQUEST\fP you'll still see libcurl

act as if it sent a HEAD even when it does send a GET.

For example:

With the HTTP protocol when you tell libcurl to do a HEAD request, but then

specify a GET though a custom request libcurl will still act as if it sent a

HEAD. To switch to a proper HEAD use \fICURLOPT_NOBODY\fP, to switch to a

proper POST use \fICURLOPT_POST\fP or \fICURLOPT_POSTFIELDS\fP and to switch

to a proper GET use CURLOPT_HTTPGET.

To switch to a proper HEAD, use \fICURLOPT_NOBODY\fP, to switch to a proper

POST, use \fICURLOPT_POST\fP or \fICURLOPT_POSTFIELDS\fP and so on.

With the POP3 protocol when you tell libcurl to use a custom request it will

behave like a LIST or RETR command was sent where it expects data to be

returned by the server. As such \fICURLOPT_NOBODY\fP should be used when

specifing commands such as DELE and NOOP for example.

Restore to the internal default by setting this to NULL.