broken slurs shorter than ties

[Werner LEMBERG]

In my opinion, the worst flaw of LilyPond's otherwise excellent
formatting, a flaw that essentially everyone encounters rather
quickly, is that broken slurs are almost always shorter than broken
ties (it should be exactly the opposite), which is butt ugly and
sometimes really hampers readability.

```
#(set-default-paper-size "a6")

{
  d'4 e' g' d' |
  d'4 e' g' d'( ~ | \break
  d'4) e' f' d' |
  d'4 e' f' d' |
}
```

I know that the handling of slurs and ties is the big elephant in the
room that nobody wants to touch because of its tremendous complexity;
I'm thus looking for a manual, easy workaround to lengthen broken
slurs instead.  While using `\shape` is certainly possible, it is not
a quick solution IMHO because of its many parameters.

Any ideas?  The LSR doesn't have something into this direction, alas.

In a similar vein, the second-most serious issue (or probably even the
most serious, actually) is that broken ties are sometimes so short
that they become invisible.  Again, it would be great to have a
command to quickly lengthen the the broken parts before and/or after
the break of a tie by a given amount.  Note that setting the
`minimum-length` is not a good solution since it needs a lot of trial
to find a good value for a particular situation.

What I envision is a command similar to `\offset` that directly
influences the optical result, i.e., if I pass value 1, say, the slur
(or tie) becomes longer by 1 unit.


    Werner