Fixed 8-bit WAV format handling (it is unsigned data).

Fixed 8-bit WAV format handling (it is unsigned data).
Fixed off-by-one checks for buffer wrap.
Increment ref count for primary buffer in CreateSoundBuffer().
Added DSBPN_OFFSETSTOP support to position notification code.
Lots of minor parameter validation checks.
Stubs for: IDirectSound_initialize(), IDirectSound_Compact(),
and IDirectSound_GetSpeakerConfig().
Fixed freq shifting with 16-bit data problem, fixed 8bit<->16bit
conversion.
Lots of thread locking for DirectSound buffers.
Dealloc primary buffer when dsound is deallocated.