Reorganize some Redis commands classes.

lib/Predis/Commands/StringSetMultiple.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace Predis\Commands;
+
+class StringSetMultiple extends Command {
+    public function getId() {
+        return 'MSET';
+    }
+
+    public function filterArguments(Array $arguments) {
+        if (count($arguments) === 1 && is_array($arguments[0])) {
+            $flattenedKVs = array();
+            $args = $arguments[0];
+            foreach ($args as $k => $v) {
+                $flattenedKVs[] = $k;
+                $flattenedKVs[] = $v;
+            }
+            return $flattenedKVs;
+        }
+        return $arguments;
+    }
+
+    protected function canBeHashed() {
+        $args = $this->getArguments();
+        $keys = array();
+        for ($i = 0; $i < count($args); $i += 2) {
+            $keys[] = $args[$i];
+        }
+        return $this->checkSameHashForKeys($keys);
+    }
+}