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.
Here are a few changes to make 64-bit build possible.
The changes are mainly to use windows api in the correct way that works for both 32-bit and 64-bit builds.
