- netcode cleanup.

This moves all parts in the Duke/Redneck modules that access ENet into net.cpp/network.cpp and changes global ENet structs to use C++ notation instead of typedefs so that anonymous definitions for them can be added where needed.
These changes are done to avoid including enet.h globally which is a major issue because this file does not work without including windows.h, making it extremely dirty.

source/rr/src/screens.cpp

@@ -618,11 +618,9 @@ FString GameInterface::statFPS()
             }
 
             // lag meter
-            if (g_netClientPeer)
-            {
-				output.AppendFormat("%d +- %d ms\n", (g_netClientPeer->lastRoundTripTime + g_netClientPeer->roundTripTime)/2,
-					(g_netClientPeer->lastRoundTripTimeVariance + g_netClientPeer->roundTripTimeVariance) / 2);
-			}
+#ifndef NETCODE_DISABLE
+            Net_PrintLag(output);
+#endif
         }
 
         if (cumulativeFrameDelay >= 1000.0)