Security fix: a buffer overrun in the old-style SCP protocol when
receiving the header of each file downloaded from the server is fixed.
Windows PuTTY now sets its process ACL more restrictively, in an
attempt to defend against malicious other processes reading sensitive
data out of its memory.
Assorted other robustness fixes for crashes and memory leaks.
We have started using Authenticode to sign our Windows executables
and installer.
