OMEdit should display newest results first

[Christian Schubert]

In connection with #2201 there is another "Unexpected behaviour":

When a second and different model is simulated, the old plot is still up front (with the old results) and the old result record is expanded in the variable browser. The new result record is added at the end and thus very hard to find for a beginner.

The old results should be collapsed and the new ones expanded. Moreover the plots should be updated with the new results (see #2201) and if a variable does not exist in the new model, the plot should be deleted/deactivated or left empty.