Log Message:
Updated abcm2ps to 8.13.6.

---- Version 8.13.6 - 2017-02-24 ----

Fix bad vertical offset of notes in percussion staves since 8.13.2
Fix clash of note and accidentals when note in other staff
	(reported by Hudson Lacerda)
Add the decorations !8va(!, !8va)!, !8vb(! and !8vb)! (%%ottava alternative)
	(asked by Hudson Lacerda)
Handle the string definition of %%stafflines
	(asked by Reinier Maliepaard)
Handle "%%pos stem hidden" (same as '0' starting length / !stemless!)
	(asked by Jakob Englhauser a long time ago!)
Extend the tempo value up to 32000 (was < 256)
	(asked by Hudson Lacerda)
Fix loss of transposition of the bass when alone in a chord indication
	(reported by Tim Goetze)
Fix loss of measure bar when followed by clef change and time skip
Fix bad output when "%%clef auto" without %%score
	(reported by Hudson Lacerda)
Fix clash of slurs with note decorations
	(reported by Hudson Lacerda)
Fix bad output file name when "%%abc-include xx.abc"
	(reported by Guido Gonzato)
Fix bad note head when !head-xx! decoration since 8.13.5 (?)
	(reported by David Lacroix)