adds cxListLast

use C99 flexible array to mark the node's payload

use named fields to access node memory

copy list items when they are added to the list

changes off_t to ptrdiff_t

adds missing assignments for new list node

adds first draft for linked list implementation

removes unnecessary cx_allocator typedef

make cx_allocator_class shared

fixes missing CUnit include dir

(0) -300 -100 -10 +10 tip