Jump, jump, jump if you feel you want to...

Sorry, that's the line from my daughter's favourite song atm...

I've fixed a few bugs in the jump routine, merely by checking key register values on Z80 vs 68K. Mario can jump now, but it's still a little too high. Aside from that, his subsequent position is tracked correctly so the jump logic is 'working' - just allowing him to jump too high (and far). An amusing side-effect is the ability to jump from one girder to the next where they converge (much like a power-up in an enhanced version of the game!)

Also started on the falling logic, thinking that perhaps Mario 'falls' from a jump and that's why he wasn't stopping. That's not the case, however, (and ironically it's the falling case that is treated like jumping) and it's quite broken so I've commented it out for now until I get jumping working properly.

The thought of commenting the jumping code is still quite daunting...