fixed static address in example to argv[]

Examples/UDPClientServer/Mainpage.dox

@@ -106,7 +106,7 @@
 
     First a \c ::UDPv4ClientSocketHandle is created. With the function
     \c writeto(senf::INet4SocketAddress, string) the string s will be written to the specified
-    address and port, which is constructed here from a  static string \c "127.0.0.1:4243". In this
+    address and port, which is constructed here from a  static string read from the console with the format \c IP:PORT. In this
     example Integers from zero to ten are send to the Server socket.
 
     The exception handling is again the same as with the server application.

Examples/UDPClientServer/udpClient.cc

@@ -33,7 +33,7 @@ int main(int argc, char const * argv[])
             senf::UDPv4ClientSocketHandle sock;
             std::stringstream s;
             s << i;
-            sock.writeto(senf::INet4SocketAddress("127.0.0.1:4243"),s.str());
+            sock.writeto(senf::INet4SocketAddress(argv[1]),s.str());
             std::cout << i << std::endl;
         }
     }