Improve summary calculation performance

* Only reload calculation data
* Make sure performance is good when a calculated object is added or changed
- avoid recreation of summary file readers
- delete all nodes in address tree representing calculated curves
- build address nodes for calculated curves

ApplicationLibCode/ProjectDataModel/Summary/RimSummaryAddressCollection.h

@@ -66,6 +66,7 @@ public:
     void updateFolderStructure( const std::set<RifEclipseSummaryAddress>& addresses, int caseId, int ensembleId = -1 );
 
     void deleteChildren();
+    void deleteCalculatedObjects();
 
     bool isEmpty() const;
     bool isEnsemble() const;