Pre-migration

This release is being made to preserve the original version of PsSp.

After this, major changes are coming:

1. Dropping Dear ImGUI and moving to FLTK.
2. Migrating to CMake.
3. Org-mode files for documentation and github pages.
4. Upgrading to newest version of sac-format
5. Rewriting SQLite3 database to be more robust.
6. Revamping the unit/integration testing.

And loads more planned for the future, a lot to do!