added .nav-flat style with child-indent support
added .nav-flat style with child-indent support

almasaeed2010/AdminLTE,oyjt/AdminLTE,garrettwong/AdminLTE,slachiewicz/AdminLTE,slachiewicz/AdminLTE,oyjt/AdminLTE,almasaeed2010/AdminLTE,garrettwong/AdminLTE,oyjt/AdminLTE