TabNote Stem/Beam/Modifier Bug Fixing

- Articulations and annotations are now correctly placed on `TabNotes`
- Adds tests for `TabNote` annotations and articulations
- Fixed a general `Annotation` positioning bug which @amitgur initially started work on for overlapping annotations, added a `StaveNote` stem down annotation justification test as well
- `applyAndGetBeams` shouldn't break on `TabNotes` any more
- `TabNote` stem directions can be now normalized on `Beam` with the `auto_stem` construction argument