Misc refactoring and bugfix

[dangiu]

This PR includes a bunch of fix and general improvement for the code.

The biggest things are:

• Updated PIO code to automatically ack (now done before sending through dat_writer) instead of manual need for it
• Changed memcard_simulation approach from state machine to linear one, more clear and maintainable
• Bunch of small fixes

I haven't been able to test these changes because part of my development setup broke, if anybody is willing to test and confirm that everything works it would be awesome. Otherwise I will do it as soon as I get new parts. I will not be able to test the stuff related to PSIO since I don't own one.

[dangiu]

There are still a few things that would be nice to fix before the merge. In particular now I needed to define the pinout in the PIO file, I haven't found a way to include external header so that they are usable by the PIO file, haven't looked to hard though. I think there may be a way otherwise it's probably possible to do via manual modification of the files processed by pioasm.

[realJoshByrnes]

I will not be able to test the stuff related to PSIO since I don't own one.

I haven't checked your changes, but loading a game via the latest UniRom should have the desired effect (it sends the game to the PicoMemCard)