Use track selection for SetTrack, SetClip and SetEnvelope

These commands now have shorter dialogs.
Also fixed SetEnvelope optionals, which were not being honoured.

src/commands/SetTrackInfoCommand.cpp

@@ -48,15 +48,22 @@ SetTrackBase::SetTrackBase(){
    mbPromptForTracks = true;
 }
 
+//Define for the old scheme, where SetTrack defines its own track selection.
+//rather than using the current selection.
+//#define USE_OWN_TRACK_SELECTION
+
 bool SetTrackBase::DefineParams( ShuttleParams & S )
 {
+#ifdef USE_OWN_TRACK_SELECTION
    S.OptionalY( bHasTrackIndex     ).Define(     mTrackIndex,     wxT("Track"),      0, 0, 100 );
    S.OptionalN( bHasChannelIndex   ).Define(     mChannelIndex,   wxT("Channel"),    0, 0, 100 );
+#endif
    return true;
 }
 
 void SetTrackBase::PopulateOrExchange(ShuttleGui & S)
 {
+#ifdef USE_OWN_TRACK_SELECTION
    if( !mbPromptForTracks )
       return;
    S.AddSpace(0, 5);
@@ -67,6 +74,7 @@ void SetTrackBase::PopulateOrExchange(ShuttleGui & S)
       S.Optional( bHasChannelIndex).TieNumericTextBox(  _("Channel Index:"), mChannelIndex );
    }
    S.EndMultiColumn();
+#endif
 }
 
 bool SetTrackBase::Apply(const CommandContext & context  )
@@ -79,9 +87,13 @@ bool SetTrackBase::Apply(const CommandContext & context  )
    while (t )
    {
       bool bThisTrack =
+#ifdef USE_OWN_TRACK_SELECTION
          (bHasTrackIndex && (i==mTrackIndex)) ||
          (bHasChannelIndex && (j==mChannelIndex ) ) ||
          (!bHasTrackIndex && !bHasChannelIndex) ;
+#else
+         t->GetSelected();
+#endif
 
       if( bThisTrack ){
          ApplyInner( context, t );
@@ -95,8 +107,6 @@ bool SetTrackBase::Apply(const CommandContext & context  )
    return true;
 }
 
-
-
 bool SetTrackStatusCommand::DefineParams( ShuttleParams & S ){ 
    SetTrackBase::DefineParams( S );
    S.OptionalN( bHasTrackName      ).Define(     mTrackName,      wxT("Name"),       wxT("Unnamed") );