Generated Synthetic Root Feature Should be Abstract

[pmbittner]

The generation of feature models from a list of feature names is implemented in FeatureModelUtils.FromOptionalFeatures and creates a synthetic root node to gather all given features as optional children. The generated root is not abstract which makes it configurable, biasing any analyses (such as #SAT). The root should be made mandatory and should probably also get a name that has a smaller changes of naming conflicts.

VEVOS_Simulation/src/main/java/org/variantsync/vevos/simulation/util/fide/FeatureModelUtils.java

Lines 33 to 35 in 1a694f7

	final Feature root = new Feature(fm, "Root");
	fm.addFeature(root);
	fm.getStructure().setRoot(root.getStructure());