Well, it looks like there is no way in heck for the pre-commit hook to figure out that the commit is an amend, so we'll have to go with the kluge.
I also added a hook to check rebases (it can't actually stop the rebase at the error, but it can at least present them afterwards, so you know what commits to stop at in an interactive rebase). To activate the new hook, you need to re-run githelper.pike after you pull it.
