Complete reorganization of the Predis\Connection namespace.

* Renamed SingleConnectionInterface to NodeConnectionInterface since
  this name is better and makes even more sense in the context of
  cluster and replication scenarios.

* Moved specialized aggregate connections (the ones implementing both
  predis and redis cluster and master/slave replication) in a newly
  created Predis\Connection\Aggregate sub-namespace.

* Removed the "Connection" part from names of aggregate connection
  interfaces in the Predis\Connection\Aggregate sub-namespace.

* Changed "Composable" to "Composite" in the name of interfaces and
  classes that can use pluggable protocol processors.

tests/Predis/Connection/ConnectionExceptionTest.php

@@ -23,7 +23,7 @@ class ConnectionExceptionTest extends CommunicationExceptionTest
     /**
      * {@inheritdoc}
      */
-    protected function getException(SingleConnectionInterface $connection, $message, $code = 0, \Exception $inner = null)
+    protected function getException(NodeConnectionInterface $connection, $message, $code = 0, \Exception $inner = null)
     {
         return new ConnectionException($connection, $message, $code, $inner);
     }