Changed multiple select for days of weekend to 'chosen'. Cleaned up some code. Removed success message when changing timezone.

removed bug, that the drag and drop function added 24h to the duration of the event, after moving an event from allday to a time

Conflicts:
	core/templates/login.php
	index.php
	lib/util.php

added jquery ui icons. otherwise its for casual users impossible to close the new event dialog in the calendar