datapicker special dates selectibel false or true

datapicker special dates selectibel false or true

Hello!
 can please explain to me how to add false and true if I wont to specila date can't be selceted (no clicible) or second option how to make other date except specila dates dates no selectible...  http://jsfiddle.net/sickworm/atkaqsww/ 
Thanks