CONTRIB-4957 :: explain about skipped questions on feedbacksections page

Signed-off-by: Joseph Rézeau <moodle@rezeau.org>
CONTRIB-4965 :: Another cast problem with Username

Signed-off-by: Joseph Rézeau <moodle@rezeau.org>
CONTRIB-4967 :: Show nonrespondents list doesn't paginate properly

Signed-off-by: Joseph Rézeau <moodle@rezeau.org>
Release  version 2.6.4 STABLE (Build - 2014033100)

Signed-off-by: Joseph Rézeau <moodle@rezeau.org>
Merge head