Added class embedElement
Added youtube video to wiki syntax and test input for it
Merge branch 'master' of github.com:Kakadu/js_of_ocaml
Spelling error fixed
Merge branch 'master' of https://github.com/Kakadu/js_of_ocaml into Kakadu-master
Examples: improved Youtube video embedding in wiki example
Examples: in wiki, use iframes for Youtube (as recommended)