add mutation observer support

[nikitin-vlad]

i have found that using mutation observer work much faster that postMessage, can you add it to your library. here are some examples
http://jsfiddle.net/6TZ9J/1/
http://jsfiddle.net/uLgcxhj7/

tested in 36 chrome

[domenic]

Please read https://github.com/YuzuJS/setImmediate#macrotasks-and-microtasks

[nikitin-vlad]

thanks for info