Updated abcm2ps to 8.13.8.

---- Version 8.13.8 - 2017-03-22 ----

Fix error on "!some deco!.|" (dotted bar)
(reported by Timm Reasbeck)
Fix bad slur direction when starting from grace note
Fix bad display when staff without notes in a brace system
Fix errors on w: when found after a restarting command and %abc-version >= 2.1
(reported by Lionel Coates)
Fix bad measure numbering when %%setbarnb before right repeat
(reported by Jean-Luc Fargere)
Fix bad measure bars when at end of line and
at start of next line since 8.13.5
(reported by Robert Edwards)

(wiz)