* Add statistics enum
* Support ensemble statistics curve as data source for regression curves
* Allow creation of regression curves from statistics curves
* Make sure regression curves are updated after source curves
* Add state to use full or user defined range for regression source data
* Add isRegressionCurve
* Make sure source stepping works when regression curves are present
* Support cross plot in plot templates
* Fix source stepping for cross plots
* Show cross plot data in "Show Plot Data"
* Use bin size and realization count when computing cross plot statistics
* Remove use of RifEnsembleStatisticsReader
* Add RimSummaryAddressSelector and RimEnsembleCrossPlotStatisticsCase
* Remove RifEnsembleStatisticsReader
* Add support for cross plot x-axis selection
* Support source stepping on ensemble cross plot curves
* Add isXAxisSummaryVector