Icons for Stuntrally + Editor, fixes #1031

Icon for **Stunt Rally**, Issue #1031 
![stuntrally](https://cloud.githubusercontent.com/assets/7050624/5172403/e32c5d50-741f-11e4-8901-c19c7e0aab13.png)



Icon for **Stunt Rally Track Editor**
![sr-editor](https://cloud.githubusercontent.com/assets/7050624/5172399/df337120-741f-11e4-8d97-f727a11528b7.png)


Alternative Icons:
![stuntrally2](https://cloud.githubusercontent.com/assets/7050624/5086570/619d6320-6f1e-11e4-8c16-f8855e5913ad.png)
![sr-editor2](https://cloud.githubusercontent.com/assets/7050624/5086572/671b6144-6f1e-11e4-9c47-9c4408fbcf4d.png)