Log Message:
Update to 0.64

* Avoid compilation error on tolower and char type.

Changelog:
2015-02-28 PuTTY 0.64 released, fixing a SECURITY HOLE

PuTTY 0.64, released today, fixes a security hole in 0.63 and before:
private-key-not-wiped-2. Also diffie-hellman-range-check has been argued
to be a security hole. In addition to these and other less critical bug
fixes, 0.64 also supports the major new feature of sharing an SSH connection
between multiple instances of PuTTY and its tools, and a command-line and
config option to specify the expected host key(s).