Fix server crash.

Author: tterrag1098

src/main/java/tterrag/treesimulator/TreeSimulator.java

@@ -28,7 +28,7 @@ public class TreeSimulator {
 
 	public static final String CHANNEL = "TGS2014";
 
-	@SidedProxy(clientSide="tterrag.treesimulator.proxy.ClientProxy")
+	@SidedProxy(clientSide="tterrag.treesimulator.proxy.ClientProxy", serverSide="tterrag.treesimulator.proxy.CommonProxy")
 	public static CommonProxy proxy;
 
 	@Instance