added alt attribute for icon images
added action value to template
formating
fixed only add piwik tracking code if piwik files exist
changed greeting string
improved mail function
improved notifications, replaced "markAsRead" js function with server side code for improved stability.
added simple module to write bulk E-Mail to registered users
changed behaviour: notification E-Mail is only send when there is no unread notification or the oldest notification is older than a month.
added helptext
fixed minor time bug when editing "allDay"-events
refactored ckeditor config files to be in a new path
added pure.css to ckeditor css