Applies suggestions from scrutinizer-ci
Adds compare() method to price item
Simplifies implementation of ProductPrice plugin
Adds test for addItem() in price item
Splits update() method of ProductLimit plugin to reduce complexity
Adds compare() method for order product items
Uses new compare() method of order product items to reduce complexity
Splits update() method of BasketLimits plugin to reduce complexity
Splits update() method of Autofill plugin to reduce complexity
Splits saveItem() method of order manager to reduce complexity