Add RSS links. Close #75.

Add links to the RSS channel in the debate, blog, events and news
views.
Merge branch 'enhancement-#75' into develop
Fix minor bug in the language selection.

Fix a minor bug in the language selection that caused errors to
appear in the admin interface.  The bug was originated by an uncontrolled
acces to a variable that could not be present in every case.
Fix minor bug in the languages