NCBC-896: Support translation between Hostname and IPAddress

Motivation
----------
The IPEndpointExtensions.GetServer(server) method, unlike the other
overloads, did not correctly handle the case where the passed in hostname
was not an IPAddress. This patch will correctly resolve the IPAddress of
the hostname.

Modifications
-------------
Updated IPEndpointExtensions.GetServer(server) so that if the value of
server is a hostname, the IPAddress will be resolved from it.

Results
-------
If a cluster is configured to use a hostname as opposed to a IPAddress,
the SDK will correctly resolve it.

Change-Id: I9de54a354c5f9e5952a0405696c92e596d01017d
Reviewed-on: http://review.couchbase.org/51237
Tested-by: Jeffry Morris <jeffrymorris@gmail.com>
Reviewed-by: Simon Baslé <simon@couchbase.com>

Src/Couchbase.Tests/Utils/IPEndpointExtensionsTests.cs

@@ -87,5 +87,14 @@ public void When_NodeAdapter_And_UseSsl_Is_True_IPEndPoint_Uses_Port_11210()
             var actual = IPEndPointExtensions.GetEndPoint(serverConfig.GetNodes()[0], clientConfig, serverConfig);
             Assert.AreEqual(expected, actual.ToString());
         }
+
+        [Test]
+        public void When_Hostname_Is_Provided_IPAdress_Is_Returned()
+        {
+            var hostname = "localhost:8091";
+            var expected = "127.0.0.1";
+            var actual = IPEndPointExtensions.GetEndPoint(hostname);
+            Assert.AreEqual(expected, actual.Address.ToString());
+        }
     }
 }

Src/Couchbase/Utils/IPEndPointExtensions.cs

@@ -21,7 +21,12 @@ public static IPEndPoint GetEndPoint(string server)
             IPAddress ipAddress;
             if (!IPAddress.TryParse(address[0], out ipAddress))
             {
-                throw new ArgumentException("ipAddress");
+                var uri = new Uri(String.Format("http://{0}", address[0]));
+                ipAddress = uri.GetIpAddress();
+                if (ipAddress == null)
+                {
+                    throw new ArgumentException("ipAddress");
+                }
             }
             int port;
             if (!int.TryParse(address[1], out port))