RF24 moved to utility folder of library. This results in one less include in sketches!

Serial flush in sleep method also means one less code in examples.
Removed set(bool) in message. Not needed. getBool just calls getInt
__attribute__((packed)) for RPI compability
Print more info in send/read debug prints.
Get internalTemp returns full degrees and uses longer Vref delay
Fix debug print gateway prepend (wrong command/type)
Fixed problem in RelayWithButton example. Now working with ack in both directions.
Serial protocol changed (incoming serial message have an new ack-parameter)

libraries/MySensors/MyGateway.cpp

@@ -114,10 +114,11 @@ void MyGateway::parseAndSend(char *commandBuffer) {
   uint8_t sensor = 0;
   uint8_t command = 0;
   uint8_t type = 0;
+  uint8_t ack = 0;
 
   // Extract command data coming on serial line
   for (str = strtok_r(commandBuffer, ";", &p);       // split using semicolon
-  		str && i < 5;         // loop while str is not null an max 5 times
+  		str && i < 6;         // loop while str is not null an max 5 times
   		str = strtok_r(NULL, ";", &p)               // get subsequent tokens
 				) {
 	switch (i) {
@@ -130,10 +131,13 @@ void MyGateway::parseAndSend(char *commandBuffer) {
 	  case 2: // Message type
 		command = atoi(str);
 		break;
-	  case 3: // Data type
+	  case 3: // Should we request ack from destination?
+		ack = atoi(str);
+		break;
+	  case 4: // Data type
 		type = atoi(str);
 		break;
-	  case 4: // Variable value
+	  case 5: // Variable value
 		value = str;
 		break;
 	  }
@@ -156,6 +160,7 @@ void MyGateway::parseAndSend(char *commandBuffer) {
 	msg.sensor = sensor;
 	msg.type = type;
 	mSetCommand(msg,command);
+	mSetAck(msg,ack==0?false:true);
 	msg.set(value);
     ok = sendRoute(msg);
     if (!ok) {