Changeset 8180

#1782:

• added CanSave property to IProblemInstanceProvider to know if it can save its data
• ProblemInstanceConsumerViewGeneric only shows the export button if an IProblemInstanceExporter is available and the selected SelectedProvider has the CanSave property set to true
• added a default implementation for CanSave and SaveData to ProblemInstanceProvider, so classes which inherit from it, don't have to implement it.
• Classes in Problems.Instances.DataAnalysis which implemented the IProblemInstanceProvider now inherit from the class ProblemInstanceProvider, so some code is obsolete now and had been deleted