[vhnemscc] Two level git

It would be nice if it were easy to set up a two-level (or multi-level?) revision control system.  On the nearer level, one can do "risky" operations like edit and delete history.  But they aren't risky, because on the farther level, any operation on the nearer level can be undone.

An ugly way to accomplish this is to wrap svk around git.