set calendar sensitive from specified date (2011-07-08)
	set calendar sensitive until specified date (2011-07-22)
	set calendar sensitive inside specified dates (from 2011-07-08 - until 2011-07-22)
	set calendar sensitive out of specified dates (until 2011-07-08 - from 2011-07-22)
	clear calendar sensitive data (make all dates sensitive)