Icon update

I simplified the icons for my own use and thought I'd pass the changes back to you if you'd like to use them. I'm happy to make modifications if you have any suggestions. I've attached a preview of how the icons look on a TwentyEleven theme compat installation.

![new-icon-preview](https://f.cloud.github.com/assets/1391994/1338345/ac458948-35e5-11e3-9b46-ca61216158f0.png)