Keyboard events for selectCheckboxMenu accessibility

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11039 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c
Visuals

git-svn-id: http://primefaces.googlecode.com/svn/primefaces/trunk@11040 5a70e874-a5cb-11dd-8af2-493fb0bb9f7c