Introduce further enhancement of the Timer Recording process:

* Disk space warning if the recording potentially will not fit in disk space available.
* ProgressDialog enhancements that allow the Stop/Cancel button to be confirmed and the elapsed time to be hidden.
* Messages enhanced to clearly show the actions being taken.

src/Project.h

@@ -283,6 +283,9 @@ class AUDACITY_DLL_API AudacityProject final : public wxFrame,
 
    bool ProjectHasTracks();
 
+   // Routine to estimate how many minutes of recording time are left on disk
+   int GetEstimatedRecordingMinsLeftOnDisk();
+
 #include "Menus.h"
 
    CommandManager *GetCommandManager() { return &mCommandManager; }