NatController: refactor some code wrt sequences of commands

This will help when adding/removing commands.

Change-Id: I154fb3d7064acddc3e067d60f225ecab6ea57ddb
diff --git a/NatController.h b/NatController.h
index 4330567..ba7daaa 100644
--- a/NatController.h
+++ b/NatController.h
@@ -42,6 +42,7 @@
     int runCmd(int argc, const char **argv);
     bool checkInterface(const char *iface);
     int setForwardRules(bool set, const char *intIface, const char *extIface);
+    int routesOp(bool add, const char *intIface, const char *extIface, char **argv, int addrCount);
 };
 
 #endif