Changes 4.69:
* Add preliminary DKIM support.
* Bugzilla 592: --help option is handled incorrectly if exim is invoked
  as mailq or other aliases.  Changed the --help handling significantly
  to do whats expected.  exim_usage() emits usage/help information.
* Added the -bylocaldomain option to eximstats.
* Bugzilla 619: Defended against bad data coming back from gethostbyaddr
* Bugzilla 613: Documentation fix for acl_not_smtp
* Bugzilla 628: PCRE update to 7.4 (work done by John Hall)

(adam)