NCBC-118: ICouchbase should extend IMemcachedClient

Change-Id: I3a0e4e3004deeef66cb7f7f646aa211498db128d
Reviewed-on: http://review.couchbase.org/20759
Tested-by: John C. Zablocki <john@couchbase.com>
Reviewed-by: Matt Ingenthron <matt@couchbase.com>

src/Couchbase/ICouchbaseClient.cs

@@ -4,7 +4,7 @@
 using Enyim.Caching;
 namespace Couchbase
 {
-	public interface ICouchbaseClient
+	public interface ICouchbaseClient : IMemcachedClient
 	{
 		object Get(string key, DateTime newExpiration);
 		T Get<T>(string key, DateTime newExpiration);