svtools: avoid -Werror=deprecated-copy (GCC trunk towards GCC 9)

...by explicitly defaulting the copy/move functions (and, where needed in turn,
also a default ctor) for classes that have a user-declared dtor that does
nothing other than an implicitly-defined one would do, but needs to be user-
declared because it is virtual and potentially serves as a key function to
emit the vtable, or is non-public, etc.

Change-Id: I206a63f4ed3468bb60505b630a42418ee14d8a0c
Reviewed-on: https://gerrit.libreoffice.org/58101
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

include/svtools/imapobj.hxx

@@ -86,6 +86,11 @@ public:
                                     bool bActive );
     virtual             ~IMapObject() {};
 
+    IMapObject(IMapObject const &) = default;
+    IMapObject(IMapObject &&) = default;
+    IMapObject & operator =(IMapObject const &) = default;
+    IMapObject & operator =(IMapObject &&) = default;
+
     virtual sal_uInt16  GetType() const = 0;
     virtual bool        IsHit( const Point& rPoint ) const = 0;