Refactor various method names to more precisely reflect
what happens
Introduce CachingOmemoStore, SignalCachingOmemoStore,
which can be either used standalone as ephemeral OmemoStore
implementations, or as wrappers around other implementations
to add a cache layer for reduced storage access.
Get rid of "isFreshInstallation". Keys are now - given
that they don't exist - generated on startup.
Bump libsignal-protocol-java to 2.6.2
Prevent offline access to some functions which require
authenticated connection
Create more advanced unit tests and integration tests
Add async initialization function for OmemoManager
Remove session handling from smack-omemo.
This is now handled - in case of smack-omemo-signal -
solely by libsignal-protocol-java
This commit adds the modules smack-omemo and smack-omemo-signal.
smack-omemo is licensed under the Apache license like the rest of the smack project.
smack-omemo-signal on the other hand is licensed under the GPLv3.
Due to the fact, that smack-omemo is not of much use without smack-omemo-signal,
the OMEMO feature can currently only be used by GPLv3 compatible software.
This may change in the future, when a more permissively licensed module becomes available.
Fixes SMACK-743.
