Remove routing information from Grob_info

Remove routing information from Grob_info

It passes information to acknowledgers that does not really belong there and instead
manages how information gets there.  Moving this information into arguments for
the various kinds of announce_grob procedure is cleaner and allows to bounce
Grob_info through Scheme without the danger of information loss.

[dak, 2016-04-27 08:31:56]

https://codereview.appspot.com/294330043/diff/1/lily/score-engraver.cc
File lily/score-engraver.cc (left):

https://codereview.appspot.com/294330043/diff/1/lily/score-engraver.cc#oldcod...
lily/score-engraver.cc:160: Engraver_group::announce_grob (info);
I guess this is the one.  Instead of START this must be start_end here.  Let's
see how much better we fare with that.

An editing error: at first I was confused into thinking Score_engraver was an
engraver (which has different calling conventions).  But Score_engraver is an
Engraver_group.

And when correcting this, I apparently overlooked one use of START.  Too bad,
the change looked for the better I think.  Now somebody just has to explain
why...

[pkx166h, 2016-04-28 06:11:08]

Instead of START this must be start_end

[Carl, 2016-04-28 14:20:34]

LGTM