* lily/include/sequential-iterator.hh (class Sequential_iterator):

* lily/include/sequential-iterator.hh (class Sequential_iterator):
bugfix: protect music list from GC.

* Documentation/user/introduction.itely: misc fixes.

* scripts/ly2dvi.py (run_latex): show latex error log. Ask for
bugreport if lilypond is killed by a signal.

* lily/beam.cc: complete rewrite of multiplicity. This fixes 16th
knees code.
(quanting): add french beaming support (property french-beaming)
(stem_beams): removed.