Actually define StorageFormat and the mechanism to register it.
Keep track of unknown fields so that things still serialize.
Allow setting storage in DDL.
Requires some care getting that storage copied into the new object at just the right time.
That uncovered another place that was using SchemaFactory wrong.
Another problem uncovered by those.
Let format decide how many instances to have.
React to merge.
merge MMcM: Actual storage formats and their registration

Merge pull request #1007 from MMcM/sql-layer/storage-format-registration
https://github.com/FoundationDB/sql-layer/pull/1007