Log Message:
audio: Add dssi from wip

Based on work by Johann Franz a very long time ago.

DSSI (pronounced "dizzy") is an API for audio processing plugins,
particularly useful for software synthesis plugins with user
interfaces.

DSSI is an open and well-documented specification developed for use
in Linux audio applications, although portable to other platforms.
It may be thought of as LADSPA-for-instruments, or something
comparable to VSTi.

DSSI consists of a C language API for use by plugins and hosts,
based on the LADSPA API, and an OSC (Open Sound Control) API for
use in user interface to host communications.  The DSSI specification
consists of an RFC which describes the background for the proposal
and defines the OSC part of the specification, and a documented
header file which defines the C API.