refactor on PanelGrid

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11828 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c
bugfix

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11829 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c
new mode for menubar

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11830 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c