For charting two's axix units type, replaced usage of older ChartAxisUnitsEnum...

For charting two's axix units type, replaced usage of older ChartAxisUnitsEnum with new CaretUnitsTypeEnum.  CaretUnitsTypeEnum supports all unit types in both NiftiTimeUnitsEnum and CiftiSeriesMap.  Also corrected order of line-series history from scene and added ability to select rows in scalar data series files.