PuTTY update 0.66

Security fix: an escape sequence which used to make PuTTY's terminal code read and potentially write the wrong memory is fixed. See vuln-ech-overflow.
Bug fix: better Unicode handling in Windows PuTTY keyboard messages, so it should now work better with WinCompose.
Bug fix: jump lists on Windows 10 should now work.
There's now a set of command-line options to enable session logging.
&P in the log file name now substitutes in the port number from the configuration.