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.
Subject to be moved elsewhere in case we decided on a more cmplete
upgrade toolset. Right now, put it here so that people can upgrade
their wtmp files if they want.
Note that the tool is not yet fully bullet-prrof. It tries to do its
best however.
