Fixes the problem that students get unauthorized message after submitting.

Add a view to see all invalidated correction lines and show only validated questionnaires to students

Tweak listboxes and the related Script to improve the peformance.

- replace objectValues with searchFolder of the List Method name
- replace searchFolder with portal_catalog in a List Method

portal_catalog > searchFolder >>> objectValues, contentValues

Left to right, faster to slower.
Especially, objectValues in a big folder produce a performance crime.
It loads all the object through ZEO.

see http://www.erp5.org/GuidelinesForCodingCrimes

to improve the paralell performance of uploading it.

This method is for avoiding ZODB Conflict erros when there are a lot of threads
and a lot of write access in the folder.

The assumption that all the profeccers edit the same answer in a same time is
not realistic. So randomise the answer url at which professers edit.

The previous version that is pinned by slapos-0.117 was a bit old.
We need newer version because recent one has several performance fixing
for instance in IdTool, MemCacheTool.