Added check to see if index exists, fixing issue #21
Added check to see if object OO (overlap-items) exists, fixing issue #19
Fixed spelling mistakes issue #37
Fixed dead link on issue #28
Added check to see if array is empty, fixing issue #40
Made float out of date value, fixing issue #27
Fixed GeneralCalendarDays - issue #38
Adde missing link editCalendarDays - issue #43
Added UI and PHP tools to prevent date mixup - issue #31
Added missing code to show error - issue #16