sample: make existed cells support swipe-operation

swipe-operation-handler

- (void)containerViewPanGestureRecognized:(UIPanGestureRecognizer *)gestureRecognizer
{
    switch (gestureRecognizer.state) {
        case UIGestureRecognizerStateBegan: {
            self.originalLocation = [gestureRecognizer locationInView:self.contentView];
            break;
        }
        case UIGestureRecognizerStateChanged: {
            CGFloat newX = [gestureRecognizer locationInView:self].x - self.originalLocation.x;

            self.contentView.frame = self.targetContentViewFrame = ({
                CGRect frame = self.contentView.frame;
                frame.origin.x = newX;
                frame;
            });
            break;
        }
        case UIGestureRecognizerStateEnded: {
            // ... do animation or operation here
            }
            break;
        }
        default:
            break;
    }
}