AxolotlStore needs to be defined in SessionBuilder.

Upgrading dependencies and passing infer tests.

Upgrading 25519 dependency

NSSecureCoding serialization of PreKeyBundles.

Adding `remoteRegistrationId` interface on SessionCipher objects.

ProtocolBuffers specification.

Adding missing MessageKeys serialization

Adding tests for out of order message decryption

Random bug fixes

Update .travis.yml

Update .travis.yml

Some fixes

Fixing typo