Add taint checking and enforcement to the tmcc "accounts" command.
Taints applied to a node are now extracted from the database and can be used wherever taint checking needs to happen in tmcd. I've applied them to the "accounts" command. tmcd will never set the "root" flag for non-admin users on OSes tainted with "useronly". It won't return any regular user accounts on nodes with the "blackbox" taint (but will pass along admin accounts).