Add regression curves to ensemble statistics curves

* 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

ApplicationLibCode/Application/Tools/RiaSummaryAddressAnalyzer.cpp

@@ -469,6 +469,8 @@ void RiaSummaryAddressAnalyzer::computeQuantityNamesWithHistory() const
 //--------------------------------------------------------------------------------------------------
 void RiaSummaryAddressAnalyzer::analyzeSingleAddress( const RifEclipseSummaryAddress& address )
 {
+    if ( !address.isValid() ) return;
+
     if ( address.category() == SummaryCategory::SUMMARY_TIME )
     {
         m_onlyCrossPlotCurves = false;