* lily/system-start-delimiter-engraver.cc

* lily/system-start-delimiter-engraver.cc
(acknowledge_system_start_delimiter): use
add_offset_callback(). This fixes translation of nested
staffgroups.

* lily/grob-closure.cc (add_offset_callback): only encaps in
simple_closure if it's a procedure.

* lily/span-bar.cc (calc_glyph_name): read glyph-name, not glyph
from bar-line.

* ly/engraver-init.ly (RemoveEmptyRhythmicStaffContext): add
remove-empty where pertinent.