Changes

The '''accessory_data''' unit class is the superclass for all ''accessory_*_data'' classes and defines basic UI attributes and compatibility/interactions between accessories. It is generally not used ''directly'' because it doesn't affect the vehicle visually or physically. Instead, more specialized [[#Subclasses|subclasses]] have been derived from it to define specific accessory types. Basically, think of '''accessory_data''' as a template from which all ''accessory_*_data'' classes have been derived.