More work on CBLDatabase (ReactiveCouchbaseLite).
Oops.
Updates list of untested methods.
Improves -[CBLDatabase (ReactiveCouchbaseLite) rcl_databaseChangeNotifications].
Adds CBLRevision (ReactiveCouchbaseLite).
Adds CBLSavedRevision (ReactiveCouchbaseLite).
Adds CBLUnsavedRevision (ReactiveCouchbaseLite).
Adds CBLDocument (ReactiveCouchbaseLite).