Applied icalendar patches from Niels Giesen.

Applied icalendar patches from Niels Giesen.

lisp/ChangeLog:

2011-04-27  Niels Giesen <niels.giesen@gmail.com>

	* calendar/icalendar.el (diary-lib): Added require statement.
	(icalendar--create-uid): Read out a uid from a text-property on
	the first character in the entry. This allows for code to add its
	own uid to the entry.
	(icalendar--convert-float-to-ical): Add export of
	`diary-float'-entries save for those with the optional DAY