Fix: Crash when setSelectedDate to nil - Also fix #9
Fix: Crash when setSelectedDate to nil - Also fix #9

hanhailong/PDTSimpleCalendar,gagansingh/PDTSimpleCalendar,wjszf/PDTSimpleCalendar,leasual/PDTSimpleCalendar,jivesoftware/PDTSimpleCalendar,AlexanderMazaletskiy/PDTSimpleCalendar,pengleelove/PDTSimpleCalendar,makingspace/PDTSimpleCalendar,z8927623/PDTSimpleCalendar,MichelleTessier/PDTSimpleCalendar,archfear/PDTSimpleCalendar,msdgwzhy6/PDTSimpleCalendar,BlessNeo/PDTSimpleCalendar,duanhjlt/PDTSimpleCalendar,hejunbinlan/PDTSimpleCalendar,RyanTech/PDTSimpleCalendar,keleyundou/PDTSimpleCalendar,13983441921/PDTSimpleCalendar,AlanJN/PDTSimpleCalendar,z514306470/PDTSimpleCalendar,Magnat12/PDTSimpleCalendar,MrZhuGe/PDTSimpleCalendar,hanangellove/PDTSimpleCalendar,scorpiozj/PDTSimpleCalendar,triposo/PDTSimpleCalendar,wushenchao/PDTSimpleCalendar,adonoho/PDTSimpleCalendar,asd197203/PDTSimpleCalendar,GangWang/PDTSimpleCalendar,markGilchristBookingBug/PDTSimpleCalendar,ryanhoo/PDTSimpleCalendar,ybbaigo/PDTSimpleCalendar,zzdhidden/PDTSimpleCalendar,thefuntasty/TFCalendar,SampleLiao/PDTSimpleCalendar