Fixed headers and copy constructor

ex02/Cat/Cat.cpp

@@ -28,8 +28,7 @@ Cat::~Cat()
 Cat::Cat(const Cat &other) : Animal(other)
 {
     std::cout  << "Cat copied" <<  std::endl;
-    this->brain = NULL;
-    *this = other;
+    this->brain = new Brain(*other.brain);
 }
 
 Cat& Cat::operator=(const Cat &other)