finished implementation of updated flattener transforms

.../jastadd/flatter/transforms/ServiceChannelTransforms.jadd

src/main/jastadd/flatter/transforms/SignalTransforms.jadd

src/main/jastadd/flatter/transforms/TopicTransforms.jadd

src/main/java/de/tudresden/inf/st/pnml/flatter/Main.java

...esden/inf/st/pnml/flatter/template/TemplateConstants.java

...esden/inf/st/pnml/flatter/transform/ReferenceFlatter.java

...en/inf/st/pnml/flatter/transform/TransformationUtils.java

src/main/resources/templates/ServiceMultiplexerTemplate.pnml