* input/regression/spacing-to-grace.ly: new file.

* input/regression/spacing-to-grace.ly: new file.

* input/regression/spacing-end-of-line.ly: new file.

* lily/note-spacing.cc (get_spacing): take into account breakable
stuff sticking out at the left (time sig change at line break).

* lily/spacing-spanner.cc (breakable_column_spacing): junk weird
raggedright code.

* scm/music-functions.scm (make-voice-props-set): add
staff-position for mm rests.

* lily/spacing-spanner.cc (musical_column_spacing): shrink space
before grace notes a little.