possibility for sending cookies with feed updates

this is used for Tumblr, which now redirects to a GDPR approval page in the EU
just supply two cookies in cookies.txt, namely "pfp" and "pfu"
the file is in Netscape format (see http://www.cookiecentral.com/faq/#3.5)
the file needs to be writable for the update process

.gitignore

@@ -5,4 +5,5 @@ fof.log
 fof-install.log
 *.db
 *~
-
+cookies.txt
+.idea

cookies.txt.dist

@@ -0,0 +1,4 @@
+# Netscape HTTP Cookie File
+# https://curl.haxx.se/docs/http-cookies.html
+# This file was generated by libcurl! Edit at your own risk.
+

fof-main.php

@@ -846,6 +846,15 @@ function fof_parse($url)
 
 	$pie = fof_new_parser();
 	$pie->set_feed_url($url);
+
+	// do we have a cookie file?
+    if ( is_readable ( $cookiestxt = dirname(__FILE__) . '/cookies.txt' ) ) {
+        $pie->set_curl_options(array(
+            CURLOPT_COOKIEFILE => $cookiestxt,
+            CURLOPT_COOKIEJAR => $cookiestxt
+        ) );
+    }
+
 	$pie->init();
 
 	/* A feed might contain data before the <?xml declaration, which will cause