Allow hyperdbs to replicate /w different shared keys

[hackergrrl]

It would be awesome if two users created hyperdbs separate from each other, but were still able to replicate their data to each other. As is, a single user must create a root hyperdb that all others must be derived from, which makes it difficult for users who created data and want to share, but did not know of each other initially.

[RangerMauve]

This could probably be solved by them cloning all the data over from one archive into the other, though that would lose history.