Nano platform needs assert.h explicitly. Added.

Author: dirkx

examples/JSONObject/JSONObject.ino

@@ -8,6 +8,7 @@
 */
 
 #include <Arduino_JSON.h>
+#include <assert.h>
 
 const char input[] = "{\"result\":true,\"count\":42,\"foo\":\"bar\"}";
 
@@ -132,4 +133,4 @@ void demoCreation() {
 
   Serial.print("myObject = ");
   Serial.println(myObject);
-}
+}