Add virtual_oss and it's graphical control panel virtual_oss_ctl.

Virtual OSS is an audio mixing application that multiplexes and demultiplexes
a single OSS device into multiple customizable OSS compatible devices using
character devices in userspace. These devices can be used to record played
back audio and mix the individual channels in multiple ways. Virtual OSS
also supports playback and recording through bluetooth audio devices.

Submitted by: Hans Petter Selasky