More symlink/directory troubles

This is a follow up to the original thread and patch at http://article.gmane.org/gmane.comp.version-control.git/122297. There was a bug report about problems when a directory is replaced with a symlink. I said that the patch fixed the bug for me, but I didn't test thoroughly enough, because it turns out there are 3 bugs, and the patch only fixed one of them.

I am sending some test scripts to demonstrate the bugs in hopes of spurring some activity here. I think the convention is to use test_expect_failure for this sort of test, so that's what I did.

Unfortunately I have very little time in the next 2 weeks, so I probably won't be able to do much more than send the tests, and fix them up if necessary. In 2 weeks I can take a look at the C code, if it isn't already fixed by then.

James