Log Message:
Updated abcm2ps to 8.13.12.

---- Version 8.13.12 - 2017-07-03 ----

Fix bad height of SVG images when lyrics under the staff
	(reported by Manavasu)
Don't display ottava decorations on secondary voices
	(reported by Willem Vree)
Fix loss of measure bar when followed by %%score and voice absent
	(reported by Simon Wascher)