STATUS/FLAGS works in simulator, as do jumps

Implemented basic STATUS/FLAGS support in the functional simulator and made numerous bug fixes so now the jmp and jmpz tests now run successfully, as does the mode test.

Next steps will be to implement paging in the functional simulator, which first requires I re-learn how paging actually works. As part of that, I should create some better documentation so people other than me (or future-me), can someday understand it.