* lily/tuplet-bracket.cc (after_line_breaking): don't suicide if

* lily/tuplet-bracket.cc (after_line_breaking): don't suicide if
columns is empty

* lily/tuplet-engraver.cc (finalize): new function. Reset right
bounds to currentCommandColumn for the last step.
(start_translation_timestep): if tupletFullLength is set, set
bound to Paper Column

* lily/spacing-loose-columns.cc (set_loose_columns): space a whole
clique of loose columns, eg. a set of grace notes in strict
notespacing.

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

* lily/spacing-determine-loose-columns.cc: new file.

* input/regression/spacing-strict-notespacing.ly: new file.

* lily/spacing-spanner.cc (generate_springs): rename from
do_measure.
(generate_pair_spacing): new function.
(init, generate_pair_spacing): set between-cols for floating
nonmusical columns.

* lily/tuplet-bracket.cc (print): on the left, the overshoot is
relative to the right edge of the prefatory matter.