Drop support for streamable multibulk responses.

Supporting this feature has been problematic and leaded to some ugly
code to make abstractions such as pipelines and transactions aware of
these kind of response objects. Furthermore, it was not possible to
add them to all the connection classes due to implementation limits.

For such reasons Predis do not support them globally anymore, but the
actual classes are still shipped within the library so that they can
be used to build custom stuff at a level lower than client (that is,
unless we decide to remove them for good before going stable).

lib/Predis/Pipeline/MultiExecExecutor.php

@@ -11,7 +11,6 @@
 
 namespace Predis\Pipeline;
 
-use Iterator;
 use SplQueue;
 use Predis\ClientException;
 use Predis\ResponseErrorInterface;
@@ -92,38 +91,7 @@ class MultiExecExecutor implements PipelineExecutorInterface
             throw new ClientException("Invalid number of replies [expected: ".count($commands)." - actual: ".count($responses)."]");
         }
 
-        $consumer = $responses instanceof Iterator ? 'consumeIteratorResponse' : 'consumeArrayResponse';
-
-        return $this->$consumer($commands, $responses);
-    }
-
-    /**
-     * Consumes an iterator response returned by EXEC.
-     *
-     * @param SplQueue $commands Pipelined commands
-     * @param Iterator $responses Responses returned by EXEC.
-     * @return array
-     */
-    protected function consumeIteratorResponse(SplQueue $commands, Iterator $responses)
-    {
-        $values = array();
-
-        foreach ($responses as $response) {
-            $command = $commands->dequeue();
-
-            if ($response instanceof ResponseObjectInterface) {
-                if ($response instanceof Iterator) {
-                    $response = iterator_to_array($response);
-                    $values[] = $command->parseResponse($response);
-                } else {
-                    $values[] = $response;
-                }
-            } else {
-                $values[] = $command->parseResponse($response);
-            }
-        }
-
-        return $values;
+        return $this->consumeArrayResponse($commands, $responses);
     }
 
     /**