! \internal Draws line graphs from the provided data. It connects all points in \a lineData, which was created by one of the "get(...)PlotData" functions for line styles that require simple line connections between the point vector they create. These are for example \ref getLinePlotData, \ref getStepLeftPlotData, \ref getStepRightPlotData and \ref getStepCenterPlotData. \see drawS