Compact icon set for Tree

I propose to use a more compact set ([famfamfam.com](http://www.famfamfam.com)) of icons for a Tree. Please see the attached image.

![umongo-20130429](https://f.cloud.github.com/assets/556770/437972/1f2978cc-b0b5-11e2-83d8-6600ee7f46ea.png)