Add abstract cache layer

app/Core/Cache/MemoryCache.php

@@ -0,0 +1,65 @@
+<?php
+
+namespace Core\Cache;
+
+/**
+ * Memory Cache
+ *
+ * @package  cache
+ * @author   Frederic Guillot
+ */
+class MemoryCache extends Base implements CacheInterface
+{
+    /**
+     * Container
+     *
+     * @access private
+     * @var array
+     */
+    private $storage = array();
+
+    /**
+     * Save a new value in the cache
+     *
+     * @access public
+     * @param  string  $key
+     * @param  string  $value
+     */
+    public function set($key, $value)
+    {
+        $this->storage[$key] = $value;
+    }
+
+    /**
+     * Fetch value from cache
+     *
+     * @access public
+     * @param  string  $key
+     * @return mixed            Null when not found, cached value otherwise
+     */
+    public function get($key)
+    {
+        return isset($this->storage[$key]) ? $this->storage[$key] : null;
+    }
+
+    /**
+     * Clear all cache
+     *
+     * @access public
+     */
+    public function flush()
+    {
+        $this->storage = array();
+    }
+
+    /**
+     * Remove cached value
+     *
+     * @access public
+     * @param  string  $key
+     */
+    public function remove($key)
+    {
+        unset($this->storage[$key]);
+    }
+}