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/thread/thread.cpp

@@ -296,7 +296,7 @@ private:
 // ----------------------------------------------------------------------------
 
 // Create a new application object
-IMPLEMENT_APP(MyApp)
+wxIMPLEMENT_APP(MyApp);
 
 MyApp::MyApp()
 {