Stacking of permissions summary and modal footer buttons

Example: 
Large viewport
![large](http://cl.ly/image/0r050Y22203d/Screen%20Shot%202014-01-28%20at%2011.59.30.png)

Small viewpoer
![small](http://cl.ly/image/1M1k3S2m1o2Z/Screen%20Shot%202014-01-28%20at%2011.58.47.png)
(There is a bug in the trash icon, but I'd like to do that in a separate PR to keep them manageable.)