New article: Introduction to Shadow DOM

Post an introductory article along with [DevBytes video](https://www.youtube.com/watch?v=Is4FZxKGqqk).
> Isn't it better to point people to [can I use](http://caniuse.com/#search=components) 

+1 (@zenorocha  Maybe use [this link](http://caniuse.com/#feat=shadowdom)?)