modernization + add TRACE_CALL variadic function to better illustrate object creation / life-cycle.

[mralexgray]

amended.. example of the AutoToDoLists' log output...

-[TodoList setUp];
-[TodoList setWithArray:(
    "Do washing",
    "Mow lawn",
    "Write an open source library",
    "Feed the cat"
)];
-[TodoItem setWithString:Do washing];
-[TodoItem setWithString:Mow lawn];
-[TodoItem setWithString:Write an open source library];
-[TodoItem setWithString:Feed the cat];
Just called +[TodoItem instancesWithArray:
    Do washing
    Mow lawn
    Write an open source library
    Feed the cat];
Note: initialise with default list from plist (setWithArray:)
Resource file:TodoList.plist
Save file:TodoList.plist
-[TodoListViewController tableView:numberOfRowsInSection:7];
-[TodoListViewController tableView:cellForRowAtIndexPath:0];
-[TodoListViewController tableView:cellForRowAtIndexPath:1];
-[TodoListViewController tableView:cellForRowAtIndexPath:2];
-[TodoListViewController tableView:cellForRowAtIndexPath:3];
-[TodoListViewController tableView:cellForRowAtIndexPath:4];
-[TodoListViewController tableView:cellForRowAtIndexPath:5];
-[TodoListViewController tableView:cellForRowAtIndexPath:6];