Add unsigned long support; addresses issues arduino-libraries#39

Author: dirkx

examples/JSONObject/JSONObject.ino

@@ -78,7 +78,14 @@ void demoCreation() {
 
   myObject["hello"] = "world";
   myObject["true"] = true;
-  myObject["x"] = 42;
+
+  myObject["x1"] = (int) 42;
+  myObject["x2"] = (long) 42;
+  myObject["x3"] = (unsigned long) 42;
+
+  int x1 = myObject["x1"];
+  long x2 = myObject["x2"];
+  unsigned long x3 = myObject["x3"];
 
   Serial.print("myObject.keys() = ");
   Serial.println(myObject.keys());

src/JSONVar.cpp

@@ -142,6 +142,11 @@ JSONVar::operator long() const
   return cJSON_IsNumber(_json) ? _json->valueint : 0;
 }
 
+JSONVar::operator unsigned long() const
+{
+  return cJSON_IsNumber(_json) ? _json->valueint : 0;
+}
+
 JSONVar::operator double() const
 {
   return cJSON_IsNumber(_json) ? _json->valuedouble : NAN;

src/JSONVar.h

@@ -49,6 +49,7 @@ class JSONVar : public Printable {
   operator bool() const;
   operator int() const;
   operator long() const;
+  operator unsigned long() const;
   operator double() const;
   operator const char*() const;