Improved event wildcard semantics and improved perf.

Event subscriptions can now have a single wildcard anywhere in their address.

I also improved the maximum performance of Nu by reintroducing the PublishChanges field in Entities. However, unlike the previous incarnation, it defaults to True, so you only need to set it when you need a performance boost and you are not listening the changes of certain entities.

And that's it! Nu's semantic model should now be both fixed and fast!

Cheers!