Closes#724
- All the notifications are gone. Only
`synchronizerConnectionStateChanged` stayed because it's used
internally. Let's deal with this one in another task.
- Synchronizer has now two new publishers (`stateStream` and
(`eventStream`) which are used to notify the client app about
what is going on. These publishers replace notifications.
- There is also new property `latestState` which can be used to get the
SDK state in synchronous manner.
- `SDKSynchronizer.status` is no longer public. It is used internally to
refresh `latestState` and emit new values from `stateStream.
- When `SDKSynchronizer.status` is update `notify()` function is
triggered. And this function is now responsible for generating new
snapshot of `SynchronizerState` and updating `latestState` and
`stateStream`.
Michal Fousek