Use std::unique_ptr<> in wxListLineData and make it movable

Don't manage the pointer lifetime manually but use a smart pointer for
it: this is simpler and allows to make this class default-movable.

Also make it non-copyable as it never actually was (copying it would
have resulted in a double free of the owned pointer).

src/generic/listctrl.cpp

@@ -409,10 +409,7 @@ wxListLineData::wxListLineData( wxListMainWindow *owner )
 {
     m_owner = owner;
 
-    if ( InReportView() )
-        m_gi = nullptr;
-    else // !report
-        m_gi = new GeometryInfo;
+    SetReportView(InReportView());
 
     m_highlighted = false;
     m_checked = false;