* scm/lily-library.scm (ordered-cons): new function.

* scm/lily-library.scm (ordered-cons): new function.
(interval-index): new function

* lily/note-head-scheme.cc (LY_DEFINE): new file.

* lily/note-head.cc (get_stem_attachment): new function.

* scm/define-markup-commands.scm (note-by-number): read 'style
property.

* input/regression/markup-note.ly: show note-head style option.

* mf/feta-bolletjes.mf (overdone_heads): fix attachment points for
triangle head.