Missing icons

Based on PR #4075 it was made possible to add icons to JToolbar popup buttons instead of the hardcoded icon-cog. This removed an icon from different views in com_finder.

This PR adds new icons, as no icomoon icon is called icon-stats, to the statistics button.

In order to test this PR, you need to test against the current staging branch, as PR #4075 is already merged.

![skrmbillede 2014-08-07 kl 00 08 06](https://cloud.githubusercontent.com/assets/1738811/3834861/2c966e06-1db6-11e4-8739-f03ad7747bae.png)