HALT bug

The implementation of this "feature" has started, but is not finished. An incomplete version can be found here [1]. All relevant information to the bug can be found here [2].

• [1]: https://github.com/LukasKalbertodt/mahboi/commit/58dccd7ca71bf94a73ab68482e7f467f0756ba1b
• [2]: https://github.com/AntonioND/giibiiadvance/blob/master/docs/TCAGBD.pdf