Log Message:
Updated abcm2ps to 8.13.9.

---- Version 8.13.9 - 2017-04-21 ----

Fix bad handling of the 4th parameter of %%tuplets
	(reported by Reinier Maliepaard)
Execute the format file in '-F' when '-H'
	(reported by Richard Robinson)
Add %%ss-pref (stylesheet prefix) as a replacement of %%abcm2ps
Fix bad colors of lyrics and chord indications when last voice has a color
	(reported by Jean-Luc Fargere)