segfault if chord() returns null pointer in note.cpp

when notes are put on a place where a rest is, there can be a crash, because of unchecked null pointer in note.cpp.

in void Note::setTrack(int val) it should be

if (chord()) {
for (int i = 0; i < chord()->dots(); ++i) {
if (_dots[i])
_dots[i]->setTrack(val);
}
}

and I haven't experienced crashes from this one, but it looks similar in
void Note::scanElements(void* data, void (*func)(void*, Element*))

if (chord()) {
for (int i = 0; i < chord()->dots(); ++i) {
if (_dots[i])
func(data, _dots[i]);
}
}

This is only a quick fix, to prevent crashes, I don't know, if this provides correct behaviour in further program execution. However, the result looks right on the sheet.

Greetings,
Friedemann