Kinetic Cannon Sprites

Provides sprites for different energy levels left in the kinetic cannon, instead of just showing you when it's got some and when it doesn't.

![ss 2014-03-03 at 10 19 11](https://f.cloud.github.com/assets/4043940/2318403/9e631a04-a366-11e3-9c13-67389049e6ea.png)