Fix compilation errors

- Recent changes broke compilation for some devices
- Update for release

Author: TMRh20

RF24.h

@@ -1421,7 +1421,7 @@ class RF24 {
  * - Clean up begin() function (reduce program size)
  *
  * v1.3.7
- * - Bug fix for startWrite() function affecting RF24 stack (all RF24 libraries)
+ * - Bug fix for writeFast() function affecting RF24 stack (all RF24 libraries)
  * - Unify Arduino & Linux constructor. Accept SPI speed in Hz as optional parameter
  * - Removal of BCM2835 SPI speed constants due to removal from BCM library
  * - Update to latest BCM2835 driver

RF24_config.h

@@ -144,7 +144,9 @@
             typedef char const char;
 
         #else // Fill in pgm_read_byte that is used, but missing from DUE
-          #include <avr/pgmspace.h>
+          #ifdef ARDUINO_ARCH_AVR
+            #include <avr/pgmspace.h>
+          #endif
           #ifndef pgm_read_byte
             #define pgm_read_byte(addr) (*(const unsigned char *)(addr))
           #endif  
@@ -168,7 +170,7 @@
         #ifndef pgm_read_word
           #define pgm_read_word(p) (*(p))
         #endif
-        #ifndef pgm_read_ptr
+        #if !defined pgm_read_ptr || defined ARDUINO_ARCH_MBED
           #define pgm_read_ptr(p) (*(p))
         #endif
         #ifndef PRIPSTR

library.json

@@ -1,12 +1,12 @@
 {
   "name": "RF24",
   "keywords": "rf, radio, wireless, spi",
-  "description": "Optimized High Speed Driver for nRF24L01(+) 2.4GHz Wireless Transceiver",
+  "description": "Radio driver, OSI layer 2 library for nrf24L01(+) modules.",
   "repository": {
     "type": "git",
     "url": "https://github.com/nRF24/RF24.git"
   },
-  "version": "1.3.8",
+  "version": "1.3.9",
   "frameworks": "arduino",
   "platforms": [
     "atmelavr",

library.properties

@@ -1,5 +1,5 @@
 name=RF24
-version=1.3.8
+version=1.3.9
 author=TMRh20
 maintainer=TMRh20,Avamander
 sentence=Radio driver, OSI layer 2 library for nrf24L01(+) modules.