Write dedication of Tor 0.2.3 to Len

Tor 0.2.3.x is stable -- once I finish the release notes I'm going to call it stable.

At that point we'll also want some text for our dedication to Len.

Compare e.g. to the one for Andreas at https://gitweb.torproject.org/tor.git/blob/tor-0.2.2.32:/ReleaseNotes

or to the one for lilo at https://gitweb.torproject.org/tor.git/blob/tor-0.1.2.13:/ReleaseNotes