Set diffserv values to AF42 + ECT

AF42 has both the properties of CS42 and the IMM bit.

Whether this has the advantages or disadvantages of just one or
the other, I don't know. With most mac80211 stacks this will
force mosh packets in the VI queue on wireless.

As for pfifo_fast, have to look it up...

src/network/network.cc

@@ -114,6 +114,12 @@ void Connection::setup( void )
     throw NetworkException( "setsockopt", errno );
   }
 #endif
+
+ /* set diffserv values to AF42 + ECT */
+  uint8_t dscp = 0x92;
+  if ( setsockopt( sock, IPPROTO_IP, IP_TOS, &dscp, 1) < 0 ) {
+    throw NetworkException( "setsockopt on tos setting", errno );
+  }
 }
 
 Connection::Connection( const char *desired_ip, const char *desired_port ) /* server */