* Reverted 0041816 to allow TXmlRegistry.DeleteKey() delete the key and all its children. It is Delphi compatible. Windows implementation of TRegistry.DeleteKey() was fixed accordingly.
* TXmlRegistry: When a key name starts with \ or / it means the absolute path to the key is specified. So ignore the currently selected key when an absolute key is requested.
* TRegIniFile: When accessing a section do not change/close the current open key.
* TRegIniFile should work properly with the XML registry. The tregistry2 test should work on any platform.