[KSUSER, KS, SYSAUDIO]

[KSUSER, KS, SYSAUDIO]
- Make pin / node / allocator create requests compatible to ms by removing obsolete slash before object class
- Return correct error code in ksuser's KsCreatePin
- ReactOS KS is now able to create audio pins in Windows XP, though playback is not yet working
- All changes except ksuser change has been verified to work with VBox 3.2.10
- KS user changes not tested yet as KSStudio not working in trunk

svn path=/trunk/; revision=49428