Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix a bug that showed up when trying to produce a database for
subdirectories, and ended up making us loop forever.

Add the username to the md5 of the commit to make it slightly more
unique.

Make the 'cvs' run quietly.

Add a tool that I've written to help with finding what other
files/revisions were changed with a particular commit.