Klever

Now users can say that particular entries of environment model specifications should be used by default for different specification sets by using flag "reference" equals to "true". This seems to be quite complicated to track in mind at development of specifications. Moreover, it looks like only all entries corresponding to the "3.14" specifications set are marked in this way now. So in #10940 I suggested to define default sets of such entries that can be appended/overwritten by particular specification sets if necessary.