Remove commented out configuration.
Remove 'org.springframework.geode:spring-geode-starter-logging' module from the runtiem classpath in the Multi-Site Caching Sample.
Include an additional Spring @Configuration class exclusively for testing that registers a Geode CacheListener to wait for the cache Region EntryEvent to occur. When the ClientCache Registers Interest (all keys) and receives the cache Region (CustomersByName) EntryEvent, then it signifies the WAN Gateways (Sender and Receiver) has replicated the Region EntryEvent between disparate sites. Client 1 creates the Region EntryEvent that Client 2 expects to see in its cache.
Resolves gh-80.