This will give us a safer and more general rollback mechanism. Rollback only
rolls back one level, strip will rollabck
to which ever rev you specify and backup the rolled back changes to a bundle
file for you, so you can always undo it.
This is not possible with rollback.

hg strip [-f] [-b] [-n] REV
strip a revision and all later revs on the same branch

We should prompt user with list of changesets to be stripped before we do, as
it will remove the specified rev and all
its descendents.

hg log -r <rev>:tip

Can run hg --config extensions.mq= strip ... for the strip command without
having to modify the users ~/.hgrc file.