Various bugfixes and features for the upcoming iidx multidisk release

[icex2]

As the title implies, this PR is a mixed bag of various things that I had to look into while working on my "iidx multidisk" that is planned to be released once I wrapped up all the work around that and got it tested.

See individual commits as changes are broken down into more digestable and scoped chunks accordingly.

For IO misfiring fix

I went through the entire code base and checked every game and IO hw emulation combination bemanitools supports right now. Here is a exhaustive list of what's affected and what's not affected (and why):

• bst/kfca: NOT affected. Uses ACIO bus which correctly handles buffering data it's internal buffer management.
• ddr/p3io: NOT affected. State reads/writes are atomic or by value and not byte buffer.
• iidx/ezusb: AFFECTED. Probably the most well known case, see https://github.com/djhackersdev/bemanitools/issues/89
• iidx/ezusb2: AFFECTED. Same as ezusb.
• iidx/bio2: NOT affected. Uses ACIO bus which correctly handles buffering data it's internal buffer management.
• jb/p3io: AFFECTED. See https://github.com/djhackersdev/bemanitools/issues/92
• jb/p4io: AFFECTED. Same as jb/p3io
• pnm/ezusb2: AFFECTED. Very similar to iidx/ezusb because of same ezusb hardware and interfaces
• sdvx/kfca: NOT affected. Uses ACIO bus which correctly handles buffering data it's internal buffer management.
• sdvx/bio2: NOT affected. Uses ACIO bus which correctly handles buffering data it's internal buffer management.