working on better visualization

- update docs and CI after merging modules
- update picture showing the newest features
- allow passing null to Dumper.read()
- cherry-picked from 2084088d
- stereotypes
  - can be configured for all nodes
  - NTAs get hidden stereotype, with borderd colored like computed relations
- added better options for DumpAst.transform()
- use blue color for computed relations
- use transparent style for null nodes
- add featureTest module for prototyping