Support for the PLAINTEXT message type is not present in the latest
protobuf definitions. Leaving it out for now since we don't have any use
case for it currently.
Update protobuf definitions and refactor message receive and decrypt
codepath to support new protocol, including various flavors of sync
messages (sent messages, contacts, and groups).
Also cleans up background.js and lets libtextsecure internalize
textsecure.processDecrypted and ensure that it is called before handing
DataMessages off to the application.
The Envelope structure now has a generic content field and a
legacyMessage field for backwards compatibility. We'll send outgoing
messages as legacy messages, and sync messages as "content" while
continuing to support both legacy and non-legacy messages on the receive
side until old clients have a chance to transition.
* Session records are now opaque strings, so treat them that way:
- no more cross checking identity key and session records
- Move hasOpenSession to axolotl wrapper
- Remote registration ids must be fetched async'ly via protocol wrapper
* Implement async AxolotlStore using textsecure.storage
* Add some db stores and move prekeys and signed keys to indexeddb
* Add storage tests
* Rename identityKey storage key from libaxolotl25519KeyidentityKey to
simply identityKey, since it's no longer hardcoded in libaxolotl
* Rework registration and key-generation, keeping logic in libtextsecure
and rendering in options.js.
* Remove key_worker since workers are handled at the libaxolotl level
now
