Nrf5 improvements (#938)

* Fix NRF5_ESB_readMessage, allways enable radio

* NRF5: fixes and improvements

- Compiles with arduino core for nRF52 (primo)
  MY_RADIO_NRF5_ESB stays unsupported with primo!

- Split ACK negation flag into
    MY_NRF5_ESB_REVERSE_ACK_TX
    MY_NRF5_ESB_REVERSE_ACK_RX

- MY_RADIO_NRF5_ESB changes to act more than NRF24

- MY_RADIO_NRF5_ESB better support for powerdown/standby

- Moved initialization from MyMainNRF5 to hwInit()

drivers/NRF5/nrf5_wiring_digital.c

@@ -32,7 +32,13 @@ void nrf5_pinMode(uint32_t ulPin, uint32_t ulMode)
 		return;
 	}
 
+#ifdef ARDUINO_ARCH_NRF52
+	// Arduino: https://github.com/arduino-org/arduino-core-nrf52
+	ulPin = g_APinDescription[ulPin].ulPin;
+#else
+	// Sandeep Mistry: https://github.com/sandeepmistry/arduino-nRF5
 	ulPin = g_ADigitalPinMap[ulPin];
+#endif
 
 	// Set pin mode according to chapter '22.6.3 I/O Pin Configuration'
 	switch (ulMode) {