[RFR] Make browser responsive (follows #54)

The browser is now responsive.

It also fix the scroll reset issue on the tree when visiting a node.

### Responsive view

![responsive](https://cloud.githubusercontent.com/assets/4641116/3149930/34ef39c6-ea70-11e3-9765-44902b97c04a.gif)


### Scroll fix

![browser-scroll](https://cloud.githubusercontent.com/assets/4641116/3157789/4ebfdf24-eafa-11e3-92d6-1e29305b30de.gif)