Most important, the heads file will now persist all the chunk descs,
too. Implicitly, it will serve as the persisted form of the
fp-to-series map.
Change-Id: Ic867e78f2714d54c3b5733939cc5aef43f7bd08d
BinaryMarshaler instead of encodable.
BinaryUnmarshaler instead of decodable.
Left 'codable' in place for lack of a better word.
Change-Id: I8a104be7d6db916e8dbc47ff95e6ff73b845ac22
Bjoern Rabenstein
Julius Volz