lots of phpdoc; fix Customers::update()

Signed-off-by: Michael Kaufmann (d00p) <d00p@froxlor.org>

lib/classes/api/commands/class.Froxlor.php

@@ -11,12 +11,19 @@
  * @copyright  (c) the authors
  * @author     Froxlor team <team@froxlor.org> (2010-)
  * @license    GPLv2 http://files.froxlor.org/misc/COPYING.txt
- * @package    Panel
+ * @package    API
+ * @since      0.10.0
  *
  */
 class Froxlor extends ApiCommand
 {
 
+	/**
+	 * checks whether there is a newer version of froxlor available
+	 * 
+	 * @throws Exception
+	 * @return string
+	 */
 	public function checkUpdate()
 	{
 		global $version, $branding;