EntityMetadataWrapperException: Invalid data value given. when deleting a field from ticket types

Ah, it looks like when i simplified access control, that did a number of bad things (like making ticket type tabs available on all events, rather than what they're tied to. I probably need to rework this menu alter.

I just pushed code that fixes the access issues and should resolve the errant %25 (or %) in the url. I'm not sure if this resolves the metadata wrapper exception, since i still haven't been able to replicate that, but i'm hoping it does.

This is squashed! Although, probably not worth review, since it's gone away with menu refactoring.