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.

demos/forty/canvas.h

@@ -39,7 +39,7 @@ public:
     void LayoutGame();
     void ShowPlayerDialog();
 
-    DECLARE_EVENT_TABLE()
+    wxDECLARE_EVENT_TABLE();
 
 private:
     wxFont* m_font;