* Set "Ctrl+Shift+S" as shortcut for "Save as..." in CvPcb and PCBnew.

This seems to me like the defacto standard for this menu command.
* Added a default filename for save as. Currently it's set to
  "Unnamed file" using _() so its translatable.
* Changed the save dialog in PCBnew to use the path of the "original"
  file as a base for the new file.

cvpcb/readwrite_dlgs.cpp

@@ -166,8 +166,8 @@ int CVPCB_MAINFRAME::SaveCmpLinkFile( const wxString& aFullFileName )
     }
     else
     {
-        wxFileDialog dlg( this, _( "Save Component Footprint Link File" ), wxGetCwd(),
-                          wxEmptyString, ComponentFileWildcard, wxFD_SAVE );
+        wxFileDialog dlg( this, _( "Save Component Footprint Link File" ), wxEmptyString,
+                          _( "Unnamed file" ), ComponentFileWildcard, wxFD_SAVE );
 
         if( dlg.ShowModal() == wxID_CANCEL )
             return -1;