C++ EventListener (C# style)

This is just as a code example for the future interviews. This is EventListener(like it is in c#) implemented in c++ .I'm using some c++11 features (like final), but you can easily remove them if you want. Check wiki-page to see usage.

Need to be done: thread-safe; safe dispose of the caller-object(which invoking a delegate); improve event-caller;


19.12.14 - added some improvements