Add enscribe 0.0.3,

Enscribe creates digital audio watermark images from
photographic images. These images can only be seen using a
third party frequency vs time display, such as Baudline
(audio/baudline).

Images are still visible even after such audio mangling
techniques as MP3/Ogg compression, reverb, chorus, etc. Heavy
EQ and flange can stripe out vertical sections, but they can
also ruin an otherwise good song as well.

PR: ports/69076
Submitted by: Jean-Yves Lefort <jylefort@brutele.be>