Use wx-prefixed macros throughout the repository.

Change {DECLARE,IMPLEMENT}_*CLASS and {DECLARE,BEGIN,END}_EVENT_TABLE
occurrences to use the wx-prefixed version of the macros.

samples/opengl/cube/cube.cpp

@@ -253,7 +253,7 @@ void TestGLContext::DrawRotatedCube(float xangle, float yangle)
 // MyApp: the application object
 // ----------------------------------------------------------------------------
 
-IMPLEMENT_APP(MyApp)
+wxIMPLEMENT_APP(MyApp);
 
 bool MyApp::OnInit()
 {