Merge pull request #499 from SquidDev-CC/ComputerCraft/hotfix/null-network

Fix ComputerCraftAPI.getWirelessNetwork() failing

src/main/java/dan200/computercraft/ComputerCraft.java

@@ -826,7 +826,7 @@ public class ComputerCraft
         return upgrades;
     }
 
-    public IPacketNetwork getWirelessNetwork()
+    public static IPacketNetwork getWirelessNetwork()
     {
         return WirelessNetwork.getUniversal();
     }