zk.override(Object, String, Function) fails to update subclass methods

zk.override At signature (Object, String, Function) fails to update subclass methods.

At zk.js line 811 it should be something like:

case "string":
dst['$' + backup] = dst[backup];
dst[backup] = src;
_overrideSub(dst, backup, dst['$'+backup], dst[backup]);
return dst;
}