Differences compared to Mockingboard:
. Only one 6522
. AY8913 is selected by address b7
Add cmd line: -sN sdmusic
Add cmd line: -mb-audit (to enable selection of additional sound cards, eg. for mb-audit)
Mockingboard or Phasor cards can be inserted into any slot.
Change Config->Sound to that slots 4+5 to be individually selected for the 3 soundcard types.
Add MockingboardCardManager class to manage multiple cards and mix the sound buffers.