Added LeoCAD Ldraw editor icon. 

Switched LDLite icon bg to dark variant to differentiate. 

![leocad](https://cloud.githubusercontent.com/assets/5674757/3260168/3161d6aa-f24b-11e3-913f-3381b144a41a.png)

![ldlite](https://cloud.githubusercontent.com/assets/5674757/3260169/32db71ee-f24b-11e3-92e8-2a09062f549e.png)