Prepend non-HTML links when downloading recursively

because it's more likely to download temporary links before they expire because it's more similar to the browsing experience

src/recur.c

@@ -118,12 +118,23 @@ url_enqueue (struct url_queue *queue, struct iri *i,
     DEBUGP (("[IRI Enqueuing %s with %s\n", quote_n (0, url),
              i->uri_encoding ? quote_n (1, i->uri_encoding) : "None"));
 
-  if (queue->tail)
-    queue->tail->next = qel;
-  queue->tail = qel;
+  if (html_allowed)
+  {
+    if (queue->tail)
+      queue->tail->next = qel;
+    queue->tail = qel;
+  }
+  else
+  {
+    if (queue->head)
+      qel->next = queue->head;
+    queue->head = qel;
+  }
 
   if (!queue->head)
     queue->head = queue->tail;
+  if (!queue->tail)
+    queue->tail = queue->head;
 }
 
 /* Take a URL out of the queue.  Return true if this operation