Fix / New : return on project page after task deletion instead of task list
navigate (next/prev) error on task of a project
navigate (next/prev) error on task of project

use the same showrefnav function setting present in task.php file (who
work fine)
Merge pull request #1697 from defrance69/patch-3

navigate (next/prev) error on task of a project
Merge branch 'develop' of github.com:Dolibarr/dolibarr into develop