[C++] Make C++ headers accept pointers and shared pointers alike

[alexanderoster]

The idea is to introduce a templated class into the C++ headers that looks similar to this code:

private:
   const T* m_ptr;

public:	
   classParam(const T* ptr)
      : m_ptr (ptr)
   {	}	

   classParam(std::shared_ptr <T> sharedptr)
   : m_ptr(sharedptr.get())
   {	}	
   
   LibXXXSDKHandle GetHandle()
   {
    if (m_ptr != nullptr)
	 return m_ptr->GetHandle();		
    return nullptr;
  }
};

This would allow to make method calls with class instances a lot cleaner and script-like, for example

objectA->Method (objectB, objectC, 5);

instead of

objectA->Method (objectB.get(), objectC.get(), 5);