Wrapped Value Type

There are a few cases where you would really like a Property to be able to take any value, not just a single Type. The Wrapped Value Type exists for those cases.

This is extremely half-baked at this time, and is only used as a way for system Properties to declare a Default Value. It would be really nice for user Properties to also be able to declare a Default Value, but this is pretty hard: there are complications around both the user interface and persistence. So for the time being, Wrapped Value Type and Default Value are for system use only.