Add bootstrap

Seems the draft of Bootstrap support with some API idea is ready to be merged into master. The shots follow ;)
Win
![2014-10-21_15h21_10](https://cloud.githubusercontent.com/assets/1939421/4723165/79dfca0c-5945-11e4-868c-382cb6e193f8.png)
![2014-10-21_15h22_00](https://cloud.githubusercontent.com/assets/1939421/4723167/7b7b1538-5945-11e4-9331-5f9ddac22b7f.png)

Android
![2014-10-21_15h03_24](https://cloud.githubusercontent.com/assets/1939421/4723182/922f44c0-5945-11e4-84c2-e49e91861b37.png)
![2014-10-21_15h19_15](https://cloud.githubusercontent.com/assets/1939421/4723186/97a15cc2-5945-11e4-937f-f24c77b7009e.png)

iOS
![2014-10-21_15h59_46](https://cloud.githubusercontent.com/assets/1939421/4723195/a95be50e-5945-11e4-8bdc-f54494a35611.png)
![2014-10-21_16h01_26](https://cloud.githubusercontent.com/assets/1939421/4723197/aac93bd0-5945-11e4-838c-99d159f432ae.png)

Mac
![2014-10-21_19h44_25](https://cloud.githubusercontent.com/assets/1939421/4723202/b9d8a6d8-5945-11e4-84b7-b46f273c2f6a.png)
![2014-10-21_19h44_54](https://cloud.githubusercontent.com/assets/1939421/4723203/bbf09822-5945-11e4-8f77-b5099c1b2b29.png)