refactor using pimpl and fix test

src/Core/Object.h

@@ -75,7 +75,7 @@ public:
 
   Object();
   Object(const Object &copy);
-  ~Object();
+  virtual ~Object();
 
   virtual const char * GetClassName() const { return "Object"; }
 
@@ -227,10 +227,7 @@ public:
 
   void PrintSelf(std::ostream &o) const;
 
-  inline const Object &operator=(const Object &copy) {
-    this->DeepCopy(copy);
-    return *this;
-  }
+  Object &operator=(const Object &other);
 
 private:
   bool addSignalImpl(SignalBase *sig, GenericMFPtr fptr, const char *name);