This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
violate disk quotas, has more robust locking, is still being developed,
etc. The main changes merged in were the ability to not fsync() the
mailbox, not do biff/comsat broadcasts, man page fixes.
