Use vector instead of array of wxDataFormats

Also rename EnableDropTarget() to EnableDropTargets(), as calling
EnableDropTarget(wxDF_XXX) would be ambiguous due to the existence of a
non-explicit wxVector ctor taking size_t (which is a mistake on its own,
but is probably not worth changing any more).

include/wx/generic/dataview.h

@@ -284,7 +284,7 @@ public:
 
 #if wxUSE_DRAG_AND_DROP
     virtual bool EnableDragSource( const wxDataFormat &format ) wxOVERRIDE;
-    virtual bool DoEnableDropTarget(const wxDataFormatArray& formats) wxOVERRIDE;
+    virtual bool DoEnableDropTarget(const wxVector<wxDataFormat>& formats) wxOVERRIDE;
 #endif // wxUSE_DRAG_AND_DROP
 
     virtual wxBorder GetDefaultBorder() const wxOVERRIDE;