added arr class and tweaked input class.

system/arr.php

@@ -0,0 +1,23 @@
+<?php namespace System;
+
+class Arr {
+
+	/**
+	 * Get an item from an array.
+	 *
+	 * @param  string  $key
+	 * @param  string  $default
+	 * @param  array   $array
+	 * @return mixed
+	 */
+	public static function get($key, $default = null, $array = array())
+	{
+		if (is_null($key))
+		{
+			return $array;
+		}
+
+		return (array_key_exists($key, $array)) ? $array[$key] : $default;
+	}
+
+}