Enable and disabling large shopping cart performance enhancements

The large shopping cart performance enhancement consists of many different elements, which can be enabled or disabled separately. The enhancements are disabled by default.

• Enable and disabling the optimized large shopping cart order commands
  To improve the performance of large shopping carts, we can optimize the OrderItemAdd, OrderItemUpdate, OrderItemDisplay, and OrderCalculate commands.

• Enable and disabling the optimized tax command
  The optimized tax command provides improved performance for sites that encounter shopping carts that include hundreds of order items or more.

• Enable and disabling the optimized shipping calculation command
  The optimized shipping calculation command provides improved performance for sites that encounter shopping carts that include hundreds of order items or more.