negative penalties.
cleanups.
* scm/page-breaking.scm (ly:optimal-page-breaks): new
file. Rewrite function.
(prev #:init-value '() #:accessor node-prev #:init-keyword #:prev)
(page #:init-value 0 #:accessor node-page-number #:init-keyword #:pageno)
(penalty #:init-value 0 #:accessor node-penalty #:init-keyword #:penalty)
- (height #:init-value 0 #:accessor node-height #:init-keyword #:height)
(lines #:init-value 0 #:accessor node-lines #:init-keyword #:lines))
(define-method (display (node <optimally-broken-page-node>) port)