Move wxAdv library contents into wxCore

This basically removes the "adv" library, even though it's still
preserved for compatibility with user make/project files referring to
it.

It is done because the distinction between "adv" and "core" was never
really clear (e.g. why wxTreeCtrl was in core but wxTreeListCtrl in
adv?) and it prevented some core classes from using adv ones.

include/wx/unix/sound.h

@@ -21,12 +21,12 @@
 // wxSound: simple audio playback class
 // ----------------------------------------------------------------------------
 
-class WXDLLIMPEXP_FWD_ADV wxSoundBackend;
-class WXDLLIMPEXP_FWD_ADV wxSound;
+class WXDLLIMPEXP_FWD_CORE wxSoundBackend;
+class WXDLLIMPEXP_FWD_CORE wxSound;
 class WXDLLIMPEXP_FWD_BASE wxDynamicLibrary;
 
 /// Sound data, as loaded from .wav file:
-class WXDLLIMPEXP_ADV wxSoundData
+class WXDLLIMPEXP_CORE wxSoundData
 {
 public:
     wxSoundData() : m_refCnt(1) {}
@@ -54,7 +54,7 @@ private:
 
 
 /// Simple sound class:
-class WXDLLIMPEXP_ADV wxSound : public wxSoundBase
+class WXDLLIMPEXP_CORE wxSound : public wxSoundBase
 {
 public:
     wxSound();
@@ -116,7 +116,7 @@ struct wxSoundPlaybackStatus
 };
 
 // Audio backend interface
-class WXDLLIMPEXP_ADV wxSoundBackend
+class WXDLLIMPEXP_CORE wxSoundBackend
 {
 public:
     virtual ~wxSoundBackend() {}