Add ui-widget to panelmenu header

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11184 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c
Fixed #6898

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11185 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c