ProjectAudioManager doesn't use ProjectWindow, which doesn't use...

ControlToolBar, after we make a system to register functions that calculate
necessary minimum widths for status bar fields.

Also let Scrubbing.cpp register its own strings.

Also be sure to size the status field sufficiently for "Playing at Speed".

src/ProjectWindow.h

@@ -53,6 +53,8 @@ public:
    wxWindow *GetMainPage() { return mMainPage; }
    wxPanel *GetTopPanel() { return mTopPanel; }
 
+   void UpdateStatusWidths();
+
    class PlaybackScroller final : public wxEvtHandler
    {
    public: