* lily/beaming-info.cc (beamify): new function: read beatLength

* lily/beaming-info.cc (beamify): new function: read beatLength
and beatGrouping from context.

* input/regression/beam-beat-grouping.ly (Module): new file.

* lily/beam.cc (get_beam_segments): generate events for
max_connect_ case too.
(get_beam_segments): read Stem::max-beam-connect.

* lily/beam-engraver.cc (typeset_beam): set right bound if unset.

* lily/beam.cc (set_beaming): read clip-edges property.
(calc_direction): don't suicide for single stem.

* lily/beaming-info.cc (best_splitpoint_index): take bool*
argument, remove 1<<15 hack. Remove clip_edges()