[Fix bug 1011044] New custom icon set

includes close, t-shirt, crown, and ~200 fewer unused icons.

![screen shot 2014-05-22 at 10 31 37 am](https://cloud.githubusercontent.com/assets/1120619/3055084/dfa8cf6e-e1bd-11e3-9497-8e3ac5e0715f.png)


Bug page: https://bugzilla.mozilla.org/show_bug.cgi?id=1011044