FastMail.FM patchset - new patches

[Rob Mueller]

> With hindsight I should probably have defined message UUIDs to be the full 
> MD5 hash: 128 bits isn't that much worse than 96 bits per message. What is 
> the CPU overhead like for calculating MD5 sums for everything on the fly?

That would have been nice, and from an integrity point of view as well, 
being able to check at any time that a message on disk matched the UUID 
simply by computing it's MD5...

Anyway, too late now, though having the first 88 bits of the MD5 as the UUID 
seems to be working quite nicely.

Rob