* lily/include/paper-score.hh (class Paper_score): remove unused prototypes.

* lily/include/paper-score.hh (class Paper_score): remove unused prototypes.

* lily/book.cc (process): add -COUNT to midi output.

* lily/score.cc (book_rendering): remove outname argument
(book_rendering): return list of Music_outputs.

* lily/global-context-scheme.cc (LY_DEFINE): remove outname argument.

* lily/book.cc (process): loop over Music_outputs returned from Score::book_rendering().

* lily/include/music-output.hh (class Music_output): smobify class.

* lily/include/paper-score.hh (class Paper_score): make members private.

* lily/performance.cc (process): return #f iso. #<undefined>. This
prevents #<undefined> leaking into GUILE-userspace.