4 issues related to rational duration factors.

4 issues related to rational duration factors.

Since it would take 2 weeks to shoo them through in order of
dependency, I am wrapping this into a single issue (first upload
includes patch from issue 2692 and will need rebasing once that went
into master).  The various commits touch different files, though.

    Implement ly:duration-scale and let ly:make-duration accept rational factors

 lily/duration-scheme.cc |   27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)


    Replace some uses of ly:duration-factor

 scm/define-event-classes.scm |    3 +--
 scm/music-functions.scm      |    8 +++-----
 scm/safe-lily.scm            |    1 +
 3 files changed, 5 insertions(+), 7 deletions(-)


    scm/song.scm: fix faulty calculation of durations.

 scm/song.scm |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)


    Fix display of tuplet music, also when nested.

 scm/define-music-display-methods.scm |   32 +++++++++++++++-----------------
 scm/display-lily.scm                 |    3 +--
 2 files changed, 16 insertions(+), 19 deletions(-)


    Add display test for nested tuplet music.

 input/regression/display-lily-tests.ly |    1 +
 1 file changed, 1 insertion(+)