Log Message:
Updated abcm2ps to 8.13.1.

Fix pango detection.

---- Version 8.13.1 - 2016-12-10 ----

Add HTML4 colors
	(asked by David Lacroix)
Fix loss of color when change on combined rests
	(reported by David Lacroix)
Fix bad treatment of lyrics (w:) since 8.13.0
	(reported by Guido Gonzato)

---- Version 8.13.0 - 2016-12-06 ----

Accept "||:" as either simple left repeat bar ("|:"), or \ 
double bar
		and left repeat bar when on 2 music lines
	(asked by Jean-Luc Zins)
Fix bad horizontal offset of word starting with a font change in w:
Change default value of %%vocalspace (23pt -> 10pt) !!compatibility!!
Fix bad vertical offset of lyrics (w:)
Don't scale the lyrics (w:) with %%staffscale value !!compatibility!!
	(reported by Lionel Coates)
Output the lyrics (w:) after the decorations !!compatibility!!
Fix some clashes of left/right annotations with notes
	(reported by Timm Reasbeck)
Fix bad tempo value when >= 128
	(reported by Jean-Luc Zins)
Do more check about the values of %%pos
Fix loss of beam breaks when %%breakoneoln and EOL followed by grace notes
	(reported by Timm Reasbeck)