[WDMAUD.DRV]

- Move the routines which interact wdmaud.sys to legacy.c
- Implement opening / closing of audio pins as well as writing / reading audio bytes from / to it
- By defining USE_MMIXER_LIB, wdmaud.drv bypasses wdmaud+sysaudio and directly writes/reads the audio bytes to portcls.

svn path=/trunk/; revision=44721