Goal 4 Part 1(a): Prevent UI flicker with ng-bind
Goal 4 Part 1(b): Trim titles when they're added
Goal 4 Part 1(c): Disallow empty titles
Goal 4 Part 2: Enable completion toggling
Goal 4 Part 3: Enable task deletion
Goal 5 Part 1: Conditionally hide the footer based on having tasks
Goal 5 Part 2: Show the correct count of items still incomplete
Goal 5 Part 3: Show/hide and include live count on the "Clear Completed" button