Add Nick Coghlan for his patch solving an issue with joining string
subclasses.
diff --git a/Misc/ACKS b/Misc/ACKS
index 1d8d40a..c296d56 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -113,6 +113,7 @@
 Mike Clarkson
 Brad Clements
 Steve Clift
+Nick Coghlan
 Josh Cogliati
 Dave Cole
 Benjamin Collar