Time to release 2.6.4!

Update to latest upstream config.guess, config.sub and libtool versions

FAQ: Bump the revision number of the forthcoming INN 2.6.2 stable rel…

…ease

Bump version for the new 2.6.1 release

Remove the paragraph about development versions in README

innxmit: tidy up GetMessageID buffer handling

    
In theory, if you could get a message with an empty message-id header
through before anything else, it would call memcpy(NULL, p, 0) which
(surprisingly) has undefined behavior.  This doesn't seem a very likely
contingency but I tidied up the code to avoid it and (hopefully) be
clearer anyway.

Thanks to Richard Kettlewell for the patch.

Typos

typos

Rewording and editing of changes for 2.5.2

* Mention --enable-keywords and --with-openssl in the default

inn.conf configuration file.

* No need to regenerate the overview when the keyword generation
code is used.