* scm/define-music-properties.scm (all-music-properties): add

* scm/define-music-properties.scm (all-music-properties): add
quoted-context-type, quoted-context-id.

* scm/lily.scm (type-check-list): new function.

* scm/lily-library.scm: new file. Generic library routines.

* lily/parser.yy (Generic_prefix_music): move typechecking out of
parser.

* ly/music-functions-init.ly: add quoteDuring function.

* lily/include/music-iterator.hh (class Music_iterator): rename
set_translator -> set_context

* lily/parser.yy (Generic_prefix_music_scm): add
MUSIC_FUNCTION_SCM_SCM_MUSIC

* scm/lily.scm (sanitize-command-option): new function. (backportme)