Git reup should be able to resume the rebase process by default

[riannucci]

Right now it instructs you to do a rebase --continue after resolving conflicts.

Reup should also have an --abort option.

It would also be worthwhile to have a reup --undo which rewinds all branches to the state they were in before the last reup.

ALSO reup should not continue the rebase if it looks like any files on the index have merge packers in them.