Email and poll author are now retrieved from the logged user

htdocs/install/mysql/migration/3.5.0-3.6.0.sql

htdocs/install/mysql/tables/llx_opensurvey_sondage.sql

htdocs/opensurvey/card.php

htdocs/opensurvey/class/opensurveysondage.class.php

htdocs/opensurvey/fonctions.php

htdocs/opensurvey/list.php

htdocs/opensurvey/public/studs.php

htdocs/opensurvey/wizard/choix_autre.php

htdocs/opensurvey/wizard/choix_date.php

htdocs/opensurvey/wizard/create_survey.php