Ensure become(node()) works rather than failing with {node_running, ...}.
Fail clearly if the node specified with '-n' is not a member of the cluster before or after.
Various fixes / improvements: with the new scheme multiple renamings will not waork, so check for them. Fix abortive renames (with a copy of the mnesia dir). Ensure we don't talk to any other nodes while backing up / restoring since that inevitably goes wrong. Split up rename/2 a bit and rename a few other things for more clarity.
Split out preparation from rename/2, and add comments.
Nicer feedback.