Fix bugs in transfer example

Inadequate testing appeared to indicate the CRC checking was at fault,
this was incorrect.

Seemed to be 2 separate bugs in transfer example:
Symptoms: Arduino would start reading 150+ KB/s and about 5000
payloads/second received after a period of time with transfers ongoing
continuously.
Fixes:
1. Remove the printf of Payload Count (same issue with %lu )
2. Prevent division into 0

examples/Transfer/Transfer.ino

@@ -43,7 +43,7 @@ void setup(void) {
   radio.setAutoAck(1);                     // Ensure autoACK is enabled
   radio.setRetries(2,15);                  // Optionally, increase the delay between retries & # of retries
   
-  //radio.setCRCLength(RF24_CRC_8); Note: The original Transfer.ino example used 8-bit CRC which was found to result in data corruption over time.
+  radio.setCRCLength(RF24_CRC_8);          // Use 8-bit CRC for performance
   radio.openWritingPipe(pipes[0]);
   radio.openReadingPipe(1,pipes[1]);
   
@@ -114,10 +114,12 @@ if(role == RX){
      }
    if(millis() - rxTimer > 1000){
      rxTimer = millis();     
-     float numBytes = (counter*32)/1000.0;
+     unsigned long numBytes = counter*32;
      Serial.print("Rate: ");
-     Serial.print(numBytes);
-     printf("KB/s \n Payload Count: %d \n\r", counter);
+     //Prevent dividing into 0, which will cause issues over a period of time
+     Serial.println(numBytes > 0 ? numBytes/1000.0:0);
+     Serial.print("Payload Count: ");
+     Serial.println(counter);
      counter = 0;
    }
   }

examples_RPi/transfer.cpp

@@ -62,7 +62,7 @@ int main(int argc, char** argv){
   radio.setDataRate(RF24_1MBPS);
   radio.setAutoAck(1);                     // Ensure autoACK is enabled
   radio.setRetries(2,15);                  // Optionally, increase the delay between retries & # of retries
-  radio.setCRCLength(RF24_CRC_16);         //Note: The original Transfer.ino example used 8-bit CRC which was found to result in data corruption over time.
+  radio.setCRCLength(RF24_CRC_8);          // Use 8-bit CRC for performance
   radio.printDetails();
 /********* Role chooser ***********/