Just whitespace.
Fix logic error.

The nofail option would still abort if the failure
happened to be the last target.
Remove unused dirs from config.
No longer need to create vcs directory, now that we're not using git.
Add nohistory configuration attribute.  Default is false.

Also moved location of the authors dir.  This is in anticipation
of creating a symlink at the top of the repo for the default stack.
Implement logic for not keeping history.

If configured to NOT keep history, then starting a revision
merely moves all the registrations to the new revision rather
than duplicating them.
Do not try to load Acme::BadExample -- it will always stall.