Merge pull request #13 from TMRh20/FixForSerial

Fixes are in (Serial & Scanner)
- include Adafruit_TinyUSB.h as required
- remove printf and delay from scanner example

Co-Authored by @2bndy5

examples/RF24/scanner/scanner.ino

@@ -49,8 +49,6 @@ void setup(void) {
   //
 
   Serial.begin(115200);
-  delay(5000);
-  printf_begin();
   Serial.println(F("\n\rRF24/examples/scanner/"));
 
   //

src/nrf_to_nrf.h

@@ -7,6 +7,10 @@
 #ifndef __nrf52840_nrf24l01_H__
 #define __nrf52840_nrf24l01_H__
 #include <Arduino.h>
+#if !defined(__MBED__) || defined(USE_TINYUSB)
+// Needed for Serial.print on non-MBED enabled or adafruit-based nRF52 cores
+#include "Adafruit_TinyUSB.h" 
+#endif
 
 #define NRF52_RADIO_LIBRARY
 #define DEFAULT_MAX_PAYLOAD_SIZE 32