Add base datepicker styles for bootstrap datepicker.

![](http://i.imgur.com/OxoYVGp.png) - default.
![](http://i.imgur.com/zoWHNL6.png) - disabled.
![](http://i.imgur.com/QMlnjZq.png) - next/previous.
![](http://i.imgur.com/DxotZrR.png) - selected.
![](http://i.imgur.com/wtGAZFD.png) - today.

![](http://i.imgur.com/DMo5pPn.png)

![](http://i.imgur.com/jRolaFa.png)

![](http://i.imgur.com/Unzavqu.png)

![](http://i.imgur.com/1R5ZoP8.png)