and replace with script to delete a user, either from a single project
or from the entire testbed. All of the DB stuff is done in the script;
the web interface no longer does anything but error checks. This is
because removing a user requires some finess in when things are
removed, and if there are any failures I wanted to make sure that the
script could be rerun on a user, without barfing.

Add lots of error checks to make sure not deleting a user who is
"important" (project head, group head, experiment head, etc).

Add "request" mode. If a project leader deletes a user from his
project, and the user has no more project memberships, show a click
button to send us email requesting the user be deleted from the
testbed.

Bottom line, project leaders can now delete users from their project,
but must ask us to delete the account from the testbed.