Added StaticJsonDocument and DynamicJsonDocument.

Removed StaticJsonArray and DynamicJsonArray.
Removed StaticJsonObject and DynamicJsonObject.
Removed StaticJsonVariant and DynamicJsonVariant.

examples/JsonUdpBeacon/JsonUdpBeacon.ino

@@ -43,9 +43,12 @@ void setup() {
 }
 
 void loop() {
-  // Allocate the root JsonObject
+  // Allocate the JSON document
   // Use arduinojson.org/assistant to compute the capacity.
-  StaticJsonObject<500> root;
+  StaticJsonDocument<500> doc;
+
+  // Make our document represent an object
+  JsonObject& root = doc.to<JsonObject>();
 
   // Create the "analog" array
   JsonArray& analogValues = root.createNestedArray("analog");