Add Tonc classic theme (gbadev-org#24) (gbadev-org#104)

* Add Tonc classic theme (gbadev-org#24)

- Add index.hbs and book.js to support new themes
- Introduce table classes for customizable styling
- Integrate new CSS with Tonc-theme styling

Expands theme options with "Tonc Classic"

* Add Tonc-theme styling to char/screenblock table

Add Tonc classic theme (gbadev-org#24) (gbadev-org#104)

* Add Tonc classic theme (gbadev-org#24)

- Add index.hbs and book.js to support new themes
- Introduce table classes for customizable styling
- Integrate new CSS with Tonc-theme styling

Expands theme options with "Tonc Classic"

* Add Tonc-theme styling to char/screenblock table

typography: disable ligatures in code blocks