Put back cog icon for multi-select batch actions

The cog icon was removed in f4b080e for whatever reason (doesn't seem clear, the commit is quite large), this commit puts that back.

Any reason why this was removed? I noticed this because the batch actions dropdown had extra left padding which looked like where an icon should've been.

Attached screenshot below of the icon back in it's place :)

![cog_icon](https://f.cloud.github.com/assets/138450/506020/c8c48a8e-bd3f-11e2-8363-1a9a47ec5404.jpg)