Added missing text in languages files for jscalendar
Had to fix some strtotime()-related issues in admin/pages/sections and module news to use with PHP4.
module news: added publish_until field to control the visibility of a news-posting by date and time
adapted news-module to use the new jscalendar, removed old one
added again keywords to news modul files
Updated news modul with features from the advanced news modul