1. corrected bug in MDI sample (which resulted in missing horz scrollbar)

2. wxRegKey::Rename() added, regtest sample shows copying/moving/renaming keys
   and values now
3. using wxLog() insread of WriteText() contorsions in the listctrl sample,
   show client data from events in the log messages

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@6270 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775