For participated we go through each row and retrieve
the last task of the case instead of the last case
of the user. So do the same for Advanced Search.
Also remove "Sent by" columns since they don't work.
fernando: Fixed some issues regarding the casesList configuration setup and the fields USR_UID and PREVIOUS_USR_UID
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1. M /trunk/workflow/engine/methods/cases/casesListExtJs.php
2. M /trunk/workflow/engine/methods/cases/proxyCasesList.php