Porting changes for Windows. A few tweaks to the generated
makefile are required to stop Windows griping about
file permissions on chmod, and since it's sometimes hard
to delete a file immediately after closing it, we have
a couple of retries built-in to the test suite now.
Note that to clean up the test root, we have to shut all the
spawned p4d's down. That means all the clients must disconnect,
so the test cases that connect have all be updated to