Balasz, breakNES and visual6502 attribution

[davidmjc]

I found and corrected several other minor errors. In particular, despite previously understanding how the sb/A decimal adjust circuit worked, I messed it up in the circuit diagram. Similarly, despite knowing that PLA line 138 has a special treatment, I forgot to include it (this is also missing in Balasz' diagram). Finally, my version of the circuit to output the B flag to the data bus was nonsensical - hopefully it is now correct! On the plus side, the idea to group the svg into logical "wires" really helps to find mistakes like this!