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/docview/docview.cpp

@@ -70,7 +70,7 @@
 // MyApp implementation
 // ----------------------------------------------------------------------------
 
-IMPLEMENT_APP(MyApp)
+wxIMPLEMENT_APP(MyApp);
 
 wxBEGIN_EVENT_TABLE(MyApp, wxApp)
     EVT_MENU(wxID_ABOUT, MyApp::OnAbout)