Fixes margin for nested ordered lists in readme

The current nested unordered and ordered lists looks funky in readmes now. This affects for instance table of contents.

This PR fixes this margin and removes top and bottom margin.

Example before and after (images):

![listbefore](https://cloud.githubusercontent.com/assets/606374/5367207/5ae0cb48-7ffa-11e4-8f76-fde7c53a1f1c.png)
---
![listafter](https://cloud.githubusercontent.com/assets/606374/5367211/5e6ffcf2-7ffa-11e4-86b8-5f3f6c518e43.png)