v0.555 to v0.600 upgrade

Here's the upgrade script, I've had 12 people test it on their sites now with only minor problems involving incompatible plugins etc.

Here's the upgrade script, I've had 12 people test it on their sites now with only minor problems involving incompatible plugins etc. Please read the instructions contained in the zip carefully, I cannot be responsible for what happens if you don't.

Thanks to those of you who tested and offered to test.

Get it from the download box on the right.