Issue #58 - add testOneShotReplicationErrorNotification() and testContinuousReplicationErrorNotification()

https://github.com/couchbase/couchbase-lite-java-core/issues/58
Issue #58 - remove testFetchRemoteCheckpointDoc() because what is being tested is covered by tests in previous commit.

https://github.com/couchbase/couchbase-lite-java-core/issues/58
update submodule