Related: #i123862# use O*String's isEmpty() method...

to check for emptiness in chart2 module

Patch-by: j.nitschke@ok.de
Review-by: hdu@apache.org
(cherry picked from commit 17b6784443432419e9aa9fddf56e5fa6c3ce4c60)

Conflicts:
	chart2/source/controller/chartapiwrapper/DiagramWrapper.cxx
	chart2/source/controller/chartapiwrapper/WrappedAxisAndGridExistenceProperties.cxx
	chart2/source/controller/chartapiwrapper/WrappedStatisticProperties.cxx
	chart2/source/controller/dialogs/ChartTypeDialogController.cxx
	chart2/source/controller/dialogs/DataBrowserModel.cxx
	chart2/source/controller/dialogs/ObjectNameProvider.cxx
	chart2/source/controller/dialogs/res_ErrorBar.cxx
	chart2/source/controller/dialogs/tp_DataSource.cxx
	chart2/source/controller/dialogs/tp_RangeChooser.cxx
	chart2/source/controller/drawinglayer/DrawViewWrapper.cxx
	chart2/source/controller/itemsetwrapper/ErrorBarItemConverter.cxx
	chart2/source/controller/itemsetwrapper/StatisticsItemConverter.cxx
	chart2/source/controller/main/ChartController.cxx
	chart2/source/controller/main/ChartController_TextEdit.cxx
	chart2/source/controller/main/ChartController_Tools.cxx
	chart2/source/controller/main/ChartController_Window.cxx
	chart2/source/controller/main/ControllerCommandDispatch.cxx
	chart2/source/controller/main/DrawCommandDispatch.cxx
	chart2/source/controller/main/ElementSelector.cxx
	chart2/source/controller/main/ObjectHierarchy.cxx
	chart2/source/controller/main/SelectionHelper.cxx
	chart2/source/controller/main/StatusBarCommandDispatch.cxx
	chart2/source/controller/main/UndoCommandDispatch.cxx
	chart2/source/model/filter/XMLFilter.cxx
	chart2/source/model/main/ChartModel_Persistence.cxx
	chart2/source/tools/ExplicitCategoriesProvider.cxx
	chart2/source/tools/InternalDataProvider.cxx
	chart2/source/tools/NamedProperties.cxx
	chart2/source/tools/ObjectIdentifier.cxx
	chart2/source/tools/PropertyHelper.cxx
	chart2/source/tools/RegressionCurveHelper.cxx
	chart2/source/tools/WrappedProperty.cxx
	chart2/source/tools/XMLRangeHelper.cxx
	chart2/source/view/axes/VCartesianAxis.cxx
	chart2/source/view/main/ChartView.cxx
	chart2/source/view/main/ShapeFactory.cxx
	chart2/source/view/main/VLegend.cxx
	chart2/source/view/main/VTitle.cxx

Change-Id: Ia013e3d1d215f7391d5bee4b4e80eedc2a3a724f