Upgrador mechanism added

Upgrador mechanism

The Upgrador class purpose is to be able to add a specific behaviour to several classes (CoreModifiable) without implementing it in the base class. An example of Upgrador is done in UIPopUp (UIPopUp.h , UIPopUp.cpp ) so you can add a “PopUp” behaviour to all type of object inheriting UIItem.

Upgrador mechanism is detailed in this Wiki page : Upgrador