* scm/page.scm (make-page): make it friendlier to call (esp. from C++)

* scm/page.scm (make-page): make it friendlier to call (esp. from C++)

* scm/layout-page-layout.scm (make-page-from-systems): new function
(optimal-page-breaks): use the new page-breaking calling convention

* scm/define-context-properties.scm (all-user-translation-properties):
add revokePageTurns

* lily/paper-column-engraver.cc (stop_translation_timestep): add
revokePageTurns  functionality. If there is a special barline within
the breakable region, break there instead of at the end of the region.

* lily/paper-book.cc (pages): use the new page-breaking calling convention