POC combined chart for line-bar

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@8857 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c
Combined Chart Feature

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@8858 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c