curl*3: added small examples

and some minor edits

docs/libcurl/curl_easy_cleanup.3

@@ -52,6 +52,16 @@ safely remove all the strings you've previously told libcurl to use, as it
 won't use them anymore now.
 .SH RETURN VALUE
 None
+.SH EXAMPLE
+.nf
+CURL *curl = curl_easy_init();
+if(curl) {
+  CURLcode res;
+  curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
+  res = curl_easy_perform(curl);
+  curl_easy_cleanup(curl);
+}
+.fi
 .SH "SEE ALSO"
 .BR curl_easy_init "(3), "