* scm/framework-ps.scm (output-preview-framework): use new name.

* scm/framework-ps.scm (output-preview-framework): use new name.

* lily/program-option.cc (internal_set_option): use new names.

* Documentation/user/SConscript (lilypond_book_flags): update -d
variable names.

* Documentation/user/lilypond-book.itely (Inserting LilyPond
output into other programs): new variable names.

* scm/lily.scm (define-scheme-options): uniformize var names.

* lily/tuplet-engraver.cc (listen_tuplet_span): verify that
tuplets_ is non-empty before popping.