* lily/font-interface.cc (get-font): take alist chain i.s.o. alist

* lily/font-interface.cc (get-font): take alist chain i.s.o. alist
argument

* scm/music-functions.scm (display-music): new function
(music-map): change arg order.

* input/regression/new-markup-syntax.scm: new file

* lily/parser.yy (markup): add \markup { .. } syntax.

* scm/new-markup.scm (override-markup): new function
(lookup-markup): new function
(music-markup): new function
(lookup-markup-command): use markup-signature to store argument
format for parser.

* lily/lexer.ll: preliminary \markup syntax.