lcl: added TPropStorageXMLConfig.LoadFromStream+SaveToStream

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@39711 4005530d-fff6-0310-9dd1-cebe43e6787f
anchordocking: restoretest: loading settings

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@39712 4005530d-fff6-0310-9dd1-cebe43e6787f