Add bulk actions

* Fix list actions styling
* Do not show item actions column when no item actions are possible
* Replaced old/unused csv export action with SimpleListAction
* Add bulk actions support

![screenshot 2014-12-29 23 06 34](https://cloud.githubusercontent.com/assets/517574/5573724/3c1a8a98-8fb1-11e4-91fc-1d47e6cc5687.png)