Snapshot 2020-03-29

Most improvements addressed the safety-engineering modules of FASTEN:

• support textual and tree-like notation for the GSN models
• improvements of GSN patterns
• enabled linking of external evidence (e.g. pdf documents) to solutions
• run arbitrary external checks from specialized solutions

Additional improvements:

• new iteration to improve the modularity of arch.base and nusmv.cbd languages
  -- including migrations for existing models
• lifting of NuSMV counterexamples for CBD
• displaying of NuSMV counterexamples as MSCs
• enhanced the supported sub-set of Promela (integration of Spin)