@zamiang: Better autosaving

![image](https://cloud.githubusercontent.com/assets/555859/4816544/8dc011a8-5ee0-11e4-9f39-34535cd141c8.png)

This just does some small things to make autosaving nicer. It debounces the article's sync method to only send ajax requests at 1 second intervals and it renders "Saving..." on change of the article or section to give back immediate feedback. There's also some small visual changes looped in.