fixes an error when using PHP5.4+
Issue #97 by David_Rothstein, micahw156: Clone node object before preview to prevent data corruption.
Merge pull request #67 from micahw156/issue97

Issue #97 by David_Rothstein, micahw156: Clone node object before preview
Merge pull request #66 from hosef/1.x

Issue #96: Fix error in menu_link_save() when using PHP 5.4+.