use readTaggedElement with pointer

GUI/Model/Beam/GrazingScanItem.cpp

GUI/Model/Beam/SourceItems.cpp

GUI/Model/Data/Data2DItem.cpp

GUI/Model/Data/DataItem.cpp

GUI/Model/Detector/DetectorItem.cpp

GUI/Model/File/DatafileItem.cpp

GUI/Model/Job/JobItem.cpp

GUI/Model/Job/JobsSet.cpp

GUI/Model/Mini/MinimizerItems.cpp

GUI/Model/Par/ParameterTreeItems.cpp

GUI/Model/Sim/InstrumentItems.cpp

GUI/Model/Tune/FitParameterItem.cpp

GUI/Model/Tune/FitParameterLinkItem.cpp

GUI/Model/Tune/FitSuiteItem.cpp