Support for stacked series

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11025 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c
Add fillAlpha option

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11027 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c
Add mouseover highlight option

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11029 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c