This operator can be used for manual feature selection, which means that the
user specifies all features to be selected. This is done by providing all and
only the features that are to be selected in TheOutputConcept. The operator
then simply copies those features from TheInputConcept to TheOutputConcept
which are present in TheOutputConcept. It can be used to get rid of features
that are not needed in later parts of the operator chain. All features in TheOutputConcept
must have a corresponding feature (with the same name) in TheInputConcept.