Replace svg icons with pngs

Ahoy Mark. Since indicator applet icons don't ever scale, and your svg icons are butchered pretty hard when rendered at 22x22 (roughly), I went ahead and created a png icon set that I think fits better with all the other default indicator icons. Hopefully you agree. A comparison follows, and thanks for the useful indicator!

##### Original
![screenshot - 09172013 - 12 07 22 am](https://f.cloud.github.com/assets/170997/1154629/1b6b1b6a-1f4f-11e3-9ae8-639f480a53d1.png)

##### Updated
![screenshot - 09162013 - 11 52 40 pm](https://f.cloud.github.com/assets/170997/1154628/1b5cdbb8-1f4f-11e3-9942-9656e43ef6a5.png)