Bug991: Pause button and command should be disabled during scrubbing...

... and they will be as soon as ctrl-mouse down.

src/AudacityApp.h

@@ -92,6 +92,8 @@ enum
    IsRealtimeNotActiveFlag= 0x10000000,  //lll
    CaptureNotBusyFlag     = 0x20000000,
    CanStopAudioStreamFlag = 0x40000000,
+   AudioStreamNotScrubbingFlag
+                          = 0x80000000,
 
    NoFlagsSpecifed        = 0xffffffff
 };