Changes for small devices

Needs core PR https://github.com/owncloud/core/pull/7235 (single line) to display properly.

This stops the file-action images to overlap with long filenames on small screens (540px wide). 
Consider that the 'Edit' button for documents does not have an image, so the alignment doesn't work and you just see a white space on the bar, so the text is visible.

![screenshot_2014-02-18-02-16-40](https://f.cloud.github.com/assets/3650670/2192016/92f2ae92-985c-11e3-93bf-1d1354fab127.png)