* scm/define-grob-interfaces.scm

* scm/define-grob-interfaces.scm
(trill-pitch-accidental-interface):
add trill-pitch-accidental-interface

* lily/dots-engraver.cc (acknowledge_rhythmic_head): only
dereference if it's really a duration.

* scm/define-grobs.scm (all-grob-descriptions): set
allow-loose-spacing for PaperColumn and
NonMusicalPaperColumn. Kludge for #110.

* lily/spacing-determine-loose-columns.cc (is_loose_column):
allow-loose-spacing property.