ECHO queries may return stale data

[dmaretskyi]

Likely caused by the root doc not being updated in time.

[wittjosiah]

Dima: It seems like this issue rarely comes up in practice -- only when you have just replicated some data, and then immediately do a query, it's generally fine if the data is stale after replication, ECHO is eventually consistent after all. But that being said, I want to give users more control over the state of the database and data version