Fix alignment/padding issues non-linux devices #78

Per #88
When receiving fragmented payloads, padding was not being added to the
frame on non-linux devices, but subtracted during reads.

- Remove padding altogether from AVR devices (#defined ARDUINO_ARCH_AVR)
- Add padding to received, fragmented payloads on non-AVR, non-Linux
devices (for 32-bit devices like ESP8266)

May have affected nRF24/RF24Mesh#71

RF24Network.cpp

@@ -515,6 +515,11 @@ IF_SERIAL_DEBUG_FRAGMENTATION_L2(for(int i=0; i< frag_queue.message_size;i++){ S
           memcpy(next_frame,&frag_queue,10);
           memcpy(next_frame+10,frag_queue.message_buffer,frag_queue.message_size);
           next_frame += (10+frag_queue.message_size);
+          #if !defined(ARDUINO_ARCH_AVR)
+          if(uint8_t padding = (frag_queue.message_size+10)%4){
+            next_frame += 4 - padding;
+          }
+          #endif
           IF_SERIAL_DEBUG_FRAGMENTATION( printf_P(PSTR("enq size %d\n"),frag_queue.message_size); );
 		  return true;
 		}else{
@@ -551,10 +556,11 @@ IF_SERIAL_DEBUG_FRAGMENTATION_L2(for(int i=0; i< frag_queue.message_size;i++){ S
 	//IF_SERIAL_DEBUG_FRAGMENTATION( for(int i=0; i<message_size;i++){ Serial.print(next_frame[i],HEX); Serial.print(" : "); } Serial.println(""); );
 
 	next_frame += (message_size + 10);
+    #if !defined(ARDUINO_ARCH_AVR)
     if(uint8_t padding = (message_size+10)%4){
       next_frame += 4 - padding;
     }
-
+    #endif
   //IF_SERIAL_DEBUG_FRAGMENTATION( Serial.print("Enq "); Serial.println(next_frame-frame_queue); );//printf_P(PSTR("enq %d\n"),next_frame-frame_queue); );
 
     result = true;
@@ -655,10 +661,11 @@ uint16_t RF24Network::read(RF24NetworkHeader& header,void* message, uint16_t max
     }
 	memmove(frame_queue,frame_queue+bufsize+10,sizeof(frame_queue)- bufsize);
 	next_frame-=bufsize+10;
+    #if !defined(ARDUINO_ARCH_AVR)
     if(uint8_t padding = (bufsize+10)%4){
       next_frame -= 4 - padding;
     }
-
+    #endif
 	//IF_SERIAL_DEBUG(printf_P(PSTR("%lu: NET Received %s\n\r"),millis(),header.toString()));
   }
 #endif