Added charting to metric file.
Adding Charting include files to MetricFile.h required adding the Charting Module to both Commands and OperationsBase CMakeLists.txt files to enable compilation.
I thought I had committed these changes to metric file charting prior to pulling from repository but I guess not.
ChartableInterface::getCaretMappableDataFile() was pure virtual but implemented identically in all implementing classes.  Since it does not require any 'member data' it is now implemented in the interface and implementation has been removed from all of the implementing classes.
Moved helper method for creating cartesian chart data from CiftiMappableDataFile to CaretMappableDataFile so that it can be used by Metric and Volume Files.  Added loading of charts from a multi-map volume file.  Added Charting library for include files in CommandLine and Test caused by addtions to VolumeFile.h
make -label-merge preserve column names