pull progress for 40 seconds

for some extreme network conditions 20 seconds may not be enough

javascript/progressbar.js

@@ -138,7 +138,7 @@ function requestProgress(id_task, progressbarContainer, gallery, atEnd, onProgre
                 return
             }
 
-            if(elapsedFromStart > 20 && !res.queued && !res.active){
+            if(elapsedFromStart > 40 && !res.queued && !res.active){
                 removeProgressBar()
                 return
             }