PATCH: Consolidate autobeaming to one property that controls it

[Carl Sorensen]

At *long* last I have completed my changes to the autobeaming rules.

The rietveld patch set is available at:

http://codereview.appspot.com/88155


The objective is to get all information that affects autobeaming in a single
place, so a single override will adjust the autobeam settings.

Autobeam settings also affect measure grouping, so the
measure_grouping_engraver needed to be rewritten as well.

Once the dust for this patch has settled, I will then attack the beam
subdivision code.

Please review this extensive patch and give me comments.

Thanks,

Carl