let RhythmicStaff use default barline extent

let RhythmicStaff use default barline extent

There is no reason to make barlines in RhythmicStaff special.
The purpose of the deleted code was probably to ensure that
the barlines were visible at all (despite the fact that there
is just one staffline in a RhythmicStaff).  However, currently
barline code takes care of this by default.

This makes barlines in DrumStaff and RhythmicStaff similar.

[Keith, 2013-11-30 05:56:50]

Looks good.

Repeat bars look fine (as they do in Drum Staff).

The book by Kurt Stone happens to have some bar-lines in single-line percussion
staves that are as tall as a 4/4 time-signature.  Other examples in the same
book have short bar-lines like these here, and looking at some scores the short
bar-lines are more common.

[janek, 2013-12-01 12:28:12]

On 2013/11/30 05:56:50, Keith wrote:
> Looks good.
> 
> Repeat bars look fine (as they do in Drum Staff).
> 
> The book by Kurt Stone happens to have some bar-lines in single-line
percussion
> staves that are as tall as a 4/4 time-signature.  Other examples in the same
> book have short bar-lines like these here, and looking at some scores the
short
> bar-lines are more common.

Thanks! I've added this as a comment in the commit message, so that anyone
curious about the background of our decision will have something to look at.

best,
Janek

[janek, 2013-12-04 23:01:39]

pushed as e8a9ef10aa3bfc2db7689aa58631aabb4095cd16

cheers,
JAnek :-)