[Denemo-devel] Getting a directive of a given tag - change to semantics

[Richard Shann]

In denemo there is a primitive routine to get a directive with a given
tag. It was returning a non-NULL value even if there was no directive
with the given tag in the case where there was some other directive
present. (Crazy).
One consequence was that d-GetDirectiveForTag-xxxx (where xxx = staff,
chord, note etc etc) was returning some other tag if it didn't find the
tag requested.
I have changed this so it returns #f

I noticed this bug because I had a staff with instrument name and the
smaller staff flag set. The smaller staff flag should toggle off when
pressed again but would not because trying to find if it was on by
expecting d-GetDirectiveForTag-staff to return #f was no good.

This is working now in git, but look out for unexplained failures
elsewhere - I have checked around a bit and think things are ok.

Richard