CommandManager, MenuManager don't use Lyrics.h, MixerBoard.h ...

... instead define new base classes in src/commands that those other
windows can inherit.  The classes have nothing but a virtual destructor.  This
lets CommandManager use dynamic_cast to detect the special windows.

See commits cbfde23 and 68e4bf6 which added the #include directives

src/Lyrics.h

@@ -16,6 +16,7 @@
 
 #include <vector>
 #include <wx/textctrl.h>
+#include "commands/CommandManagerWindowClasses.h"
 #include "widgets/wxPanelWrapper.h"
 
 class AudacityProject;
@@ -71,7 +72,9 @@ private:
 \brief LyricsPanel is a panel that paints the bouncing
 ball and the lyrics text.
 *******************************************************************/
-class LyricsPanel final : public wxPanelWrapper
+class LyricsPanel final
+   : public wxPanelWrapper
+   , public NonKeystrokeInterceptingWindow
 {
    DECLARE_DYNAMIC_CLASS(LyricsPanel)