Z80 v0.2-pre-2024-09-21

Z80 v0.2-pre-2024-04-18

Z80 v0.2-pre-2024-03-16

Z80 v0.2-pre-2023-12-16

Coding style changes; `Z_USIZE_BITS` -> `Z_USIZE_WIDTH`.

WIP

Configuration options.

This commit contains the following changes:

* The value of `Z80_OPTION_HALT_SKIP` has been changed to 4. This makes room for a 2-bit integer in the most significant bits of `Z80::options`, which may be useful for future emulation of Soviet and MME chips.
* `Z80_WITH_RETX_NOTIFICATIONS_IN_IM0` has been renamed to `Z80_WITH_IM0_RETX_NOTIFICATIONS`.
* Added `Z80_OPTION_IM0_RETX_NOTIFICATIONS` for enabling at runtime the notifications of the execution of `reti` and `retn` during the interrupt mode 0 response.
* Updated the documentation accordingly.

CMakeLists.txt

Add `Z80_OPTION_OUT_VC_255` to `Z80_MODEL_ST_CMOS` (according to resu…

…lts on real hardware).

Fixed a bug preventing the CPU from entering the HALT state due to th…

…e end of an INT signal.