* lily/accidental-engraver.cc (number_accidentals): remove

* lily/accidental-engraver.cc (number_accidentals): remove
spurious warning about non-parent contexts.

* lily/music-output-def.cc (assign_translator): \translator { }
for a Foo context implicitly redefines \FooContext.

* input/mutopia/F.Schubert/morgenlied.ly (pianoLH): many layout
fixes.

* lily/slur.cc (brew_molecule): don't use stafflinethickness
doubly in slur weight.

* input/regression/prefatory-spacing-matter.ly (TODO): add clef :|
combination.

* scm/define-grobs.scm (all-grob-descriptions): change clef -
staffbar distance.

* scripts/lilypond.py (global_latex_preamble): crank down size of
the margins. Now there is a 12 mm top and bottom margin, which
should correspond with the printable area of modern printers.

* mf/feta-accordion.mf (accreg_pen): remove circled-R, BB and SB
signs. Use \markup instead.
(accreg_pen): tweak for accordeon asterisk.