Merge branch 'adv-merge'

Move the entire contents of wxAdv library into wxCore.

In the future, wxAdv will disappear entirely, but for now keep it as an
empty placeholder to allow the existing make/project files to work.

See https://github.com/wxWidgets/wxWidgets/pull/900

include/wx/osx/sound.h

@@ -16,9 +16,9 @@
 
 #include "wx/object.h"
 
-class WXDLLIMPEXP_FWD_ADV wxSoundTimer;
+class WXDLLIMPEXP_FWD_CORE wxSoundTimer;
 
-class WXDLLIMPEXP_ADV wxSoundData
+class WXDLLIMPEXP_CORE wxSoundData
 {
 public :
     wxSoundData();
@@ -39,7 +39,7 @@ protected:
     bool m_markedForDeletion;
 } ;
 
-class WXDLLIMPEXP_ADV wxSound : public wxSoundBase
+class WXDLLIMPEXP_CORE wxSound : public wxSoundBase
 {
 public:
     wxSound();