ART Audio mark.

Members:

IG_ARTX_audio_bounds_get	Queries the bounding rectangle.
IG_ARTX_audio_bounds_set	Updates the bounding rectangle.
IG_ARTX_audio_create	Creates an instance of the mark.
IG_ARTX_audio_filename_get	Queries the file name of the annotation.
IG_ARTX_audio_filename_set	Updates the file name of the annotation.
IG_ARTX_audio_play	Plays audio sound.