Removed unused exceptions
Moved report back to core
Code generator can now handle unnamed elements
Added to the model that if the shopping cart already contains books, we first remove them before continue with the rest of the test. The example now reads the num_of_books defined in the model and also updates the same variable based on the number of items in the cart on the Amazon page when starting the test. After updating num_of_books it is also used to control the execution flow.