Fix 456: Also check for laissez-vibrer events attached to single heads inside a chord

input/regression/laissez-vibrer-chords.ly

Index: input/regression/laissez-vibrer-chords.ly
diff --git a/input/regression/laissez-vibrer-chords.ly b/input/regression/laissez-vibrer-chords.ly
new file mode 100644
index 0000000000000000000000000000000000000000..e2158794075b6b4fc445722fcdcb21de1161b290
--- /dev/null
+++ b/input/regression/laissez-vibrer-chords.ly
@@ -0,0 +1,11 @@
+\version "2.11.31"

[Neil Puttock, 2011/09/14 19:58:41]

2.15.12

+
+\header {
+  texidoc = "
+@code{\laissezVibrer} ties should also work on individual notes of a chord.
+" }
+
+\relative c' {
+  <d-\laissezVibrer g>1
+  <d^\laissezVibrer g_\laissezVibrer>1
+}