add link to web components spec

While reading the web component info, I wanted to click through to read the spec, so I added links.

Also, adjusted formatting to keep lines under 80 chars, following the link addition.

![ember_js_-_components__introduction](https://cloud.githubusercontent.com/assets/514063/2843286/15f1e3be-d07d-11e3-9b9e-a9235d89e602.png)
![ember_js_-_what_s_coming_in_ember_in_2014](https://cloud.githubusercontent.com/assets/514063/2843288/1aa182f2-d07d-11e3-94ea-e69c93b780a0.png)