add detailed sfml example

add simple wxWidgets example

CPlusPlus/wxWidgets/MyApp.cpp

@@ -0,0 +1,13 @@
+#include "MyApp.h"
+
+bool MyApp::OnInit()
+{
+    wxFrame* pFrame = new wxFrame(nullptr, wxID_ANY, "Hello World");
+
+    wxPanel* pPanel = new wxPanel(pFrame);
+    wxButton* pButton = new wxButton(pPanel, wxID_ANY, "Click me", wxPoint(10, 10), wxSize(100, 30));
+
+    pFrame->Show();
+
+    return true;
+}