Failed assertion: script with neutral direction

[Simon Albrecht]

Hello,

it would appear sensible for scripts to have neutral direction in a 
Dynamics context. However, it results in a failed assertion:

%%%%%%%%%%%%
\version "2.19.25"

\new Dynamics {
  s->
}

\layout {
  \context {
    \Dynamics
    \override Script.direction = 0
  }
}
%%%%%%%%%%%%

=>

lilypond: 
/home/gub/NewGub/gub/target/linux-64/src/lilypond-git.sv.gnu.org--lilypond.git-release-unstable/lily/lily-guile.cc:157: 
scm_unused_struct* index_get_cell(SCM, Direction): Assertion `d' failed.


It works in 2.19.16 (or did it only seem to work?), but not from .25 onward.

Best, Simon