Added MGOS library init code and Arduino.h include.

include/mgos_arduino_radiohead.h

@@ -0,0 +1,3 @@
+#include "mgos.h"
+
+bool mgos_arduino_radiohead_init(void);

src/RadioHead.h

@@ -668,6 +668,8 @@
 #ifndef RadioHead_h
 #define RadioHead_h
 
+#include "Arduino.h"
+
 // Official version numbers are maintained automatically by Makefile:
 #define RH_VERSION_MAJOR 1
 #define RH_VERSION_MINOR 61

src/mgos_arduino_radiohead.c

@@ -0,0 +1,5 @@
+#include "mgos_arduino_radiohead.h"
+
+bool mgos_arduino_radiohead_init(void) {
+  return true;
+}