Add libhv and test http client

examples/main.cpp

@@ -10,5 +10,17 @@ int main(int argc, char **argv)
 {
     auto client = new TribufuClient(0, "client_secret");
     std::cout << "client_id: " << client->get_id() << std::endl;
+
+    json json_obj = {
+        {"nome", "John"},
+        {"idade", 25},
+        {"cidade", "Exemplo"}};
+
+    std::string json_str = json_obj.dump(4);
+
+    std::cout << json_str << std::endl;
+
+    client->get_token();
+
     return 0;
 }