Indentation respects tab stops now, fix #2672

![gifrecord_2014-06-23_230105](https://cloud.githubusercontent.com/assets/5219415/3363937/ac3e74c4-fb19-11e3-8499-0781b5c94ae2.gif)

I choose a tab length of 7 (I use 2 in production, I promise!) to show how nicely it aligns now. I'm not sure if there are other occurrences this behaviour needs to be fixed so I added no specs yet.

:octocat: