New "Property" classes requiring Persistent

Hey all,

I use Property-type classes for all sorts of things, usually for Cayenne
related activities...but sometimes they're really useful on POJOs too.  The
new Property related classes (like EntityProperty) require the class to be
a subclass of Persistent.  I can't see where this is actually
relevant...but I might be missing something.  Any reason we couldn't remove
this restriction?

Thanks,

Lon

P.S. -- Still wishing these also implemented Serializable :P