Move ambitus print callback to scheme.

[hanwenn]

Nice to see this type of code migrate to Scheme.



http://codereview.appspot.com/110047/diff/1/11
File scm/output-lib.scm (right):

http://codereview.appspot.com/110047/diff/1/11#newcode778
Line 778: (ly:grob-suicide! grob)
this does not make sense. did you forget to check the length of the
noteheads array? - why would someone not set join-heads?

http://codereview.appspot.com/110047/diff/1/11#newcode782
Line 782: (head-up (ly:grob-array-ref heads 1))
you need to check the length of the array

http://codereview.appspot.com/110047/diff/1/11#newcode795
Line 795: (x-ext (cons (/ (- width) 2) (/ width 2)))
this looks like a nice candidate for a small function

  (symmetric-interval (/ width 2))

http://codereview.appspot.com/110047/diff/1/11#newcode801
Line 801: (ly:grob-suicide! grob))))))
it would be nice to explicitly return something, eg '() in the suicide
case - with all the nesting it is hard to tell what the final result is.

http://codereview.appspot.com/110047