Changes

Summary

1. NEWS for VSCode;
2. merged
3. more documentation;
4. added node_name(String): imitate jEdit buffer operations; more uniform get_file_content for external source file references;
5. tuned;
6. tuned signature;
7. avoid immediate editor.flush on buffer events;
8. refer to internal File_Model instead of external file;
9. tuned;
10. resolve dependencies implicitly via File_Model, without jEdit Buffer_Model;
11. tuned;
12. support for bibtex entries;
13. tuned;
14. tuned signature;
15. more explocit Document_Model.Content;
16. refer to bibtex entries via general Document_Model, instead of editor buffers;
17. clarified modules;
18. uniform Document.Model.node_edits (without void edits);
19. clarified check_thy_reader: check node_name here;
20. more uniform node_header (non-strict); removed dead code;
21. tuned signature;
22. tuned signature;
23. tuned;
24. clarified lazy text content;
25. Line.Document consists of independently allocated strings; tuned signature;
26. obsolete;
27. clarified buffer events: exit model while loading; misc tuning;
28. separate Buffer_Model vs. File_Model; misc tuning and clarification;
29. tuned;
30. tuned;
31. tuned;
32. manage buffer models as explicit global state; tuned signature;
33. tuned signature;