Keychain Plugin rewritten

With the next prerelease we include a new Keychain plugin part as part of the Mac plugin.
Apple changed the APIs some time ago and our existing Keychain plugin still used Mac OS 8 APIs. So now we are using newer APIs from 10.6/10.7.

There are several ways to use the keychain:

You can use the simply functions like AddGenericPassword/AddInternetPassword to add a password and FindInternetPassword/FindGenericPassword to query them back.
You can use the KeychainItemMBS and KeychainMBS classes to work on keychains and items directly.
You can use the query based functions which work with dictionaries. That are the newest functions Apple added.

In any case we hope you enjoy the updated classes. Please report any issues you see. The biggest plugin in space...