Changes to GraphicEngine/StateMenu introduced

Graphic Engine : preparation for map rendering + additional safety
checks for attempts of requesting graphics for non-existant elements.

StateMenu : We can now successfully run the game without any errors,
although the taken approach must be changed, as it's only a temporary
solution to the problem, and it introduced unncecessary mess into the
code.

Memory Deallocation : Finally All menus, buttons, texts, classIcons are
being deallocated without memory violations.