Linty fixes

This commit fixes a number of warnings shown in compilation with MSVC.  No behavioral changes intended.  I did not fix signed/unsigned warnings.

src/LabelTrack.cpp

@@ -1595,7 +1595,7 @@ void LabelTrack::HandleGlyphClick
          float t = 0.0;
          // We move if we hit the centre, we adjust one edge if we hit a chevron.
          // This is if we are moving just one edge.
-         hit.mbIsMoving = hit.mEdge & 4;
+         hit.mbIsMoving = (hit.mEdge & 4)!=0;
          // When we start dragging the label(s) we don't want them to jump.
          // so we calculate the displacement of the mouse from the drag center
          // and use that in subsequent dragging calculations.  The mouse stays

src/TrackPanel.cpp

@@ -3214,7 +3214,7 @@ void TrackInfo::DrawBordersWithin
 
    GetMuteSoloRect( rect, buttonRect, false, true, &track );
 
-   bool bHasMuteSolo = dynamic_cast<const PlayableTrack*>( &track );
+   bool bHasMuteSolo = dynamic_cast<const PlayableTrack*>( &track ) != NULL;
    if( bHasMuteSolo && !TrackInfo::HideTopItem( rect, buttonRect ) )
    {
       // above mute/solo

src/WaveTrack.cpp

@@ -2437,7 +2437,6 @@ void WaveTrack::SplitAt(double t)
    {
       if (c->WithinClip(t))
       {
-         double val;
          t = LongSamplesToTime(TimeToLongSamples(t)); // put t on a sample
          auto newClip = make_movable<WaveClip>( *c, mDirManager, true );
          c->Clear(t, c->GetEndTime());

src/blockfile/ODDecodeBlockFile.cpp

@@ -53,7 +53,7 @@ try
    mAudioFileName = std::move(audioFileName);
    mFormat = int16Sample;
 }
-catch ( const FileException & e )
+catch ( const FileException & WXUNUSED(e) )
 {
    // The constructor SimpleBlockFile sometimes throws this,
    // but it never will for the arguments that were passed to it here.
@@ -319,7 +319,7 @@ bool ODDecodeBlockFile::IsSummaryAvailable() const
 
 bool ODDecodeBlockFile::IsDataAvailable() const
 {
-   return mDataAvailable;
+   return mDataAvailable != 0;
 }
 
 /// Write the summary to disk, using the derived ReadData() to get the data

src/effects/Effect.cpp

@@ -1641,7 +1641,7 @@ bool Effect::ProcessTrack(int count,
       {
          processed = ProcessBlock(inBufPos.get(), outBufPos.get(), curBlockSize);
       }
-      catch( const AudacityException &e )
+      catch( const AudacityException & WXUNUSED(e) )
       {
          // PRL: Bug 437:
          // Pass this along to our application-level handler

src/tracks/labeltrack/ui/LabelGlyphHandle.cpp

@@ -129,7 +129,7 @@ UIHandle::Result LabelGlyphHandle::Drag
 HitTestPreview LabelGlyphHandle::Preview
 (const TrackPanelMouseState &, const AudacityProject *)
 {
-   return HitPreview( mHit.mEdge & 4 );
+   return HitPreview( (mHit.mEdge & 4 )!=0);
 }
 
 UIHandle::Result LabelGlyphHandle::Release

src/tracks/ui/SelectHandle.cpp

@@ -54,7 +54,7 @@ enum {
 
 bool SelectHandle::IsClicked() const
 {
-   return mSelectionStateChanger.get();
+   return mSelectionStateChanger.get() != NULL;
 }
 
 namespace

src/widgets/LinkingHtmlWindow.cpp

@@ -144,7 +144,7 @@ void LinkingHtmlWindow::OnLinkClicked(const wxHtmlLinkInfo& link)
          wxFileName( FileNames::HtmlHelpDir(), href.Mid( 10 ) + wxT(".htm") ).GetFullPath();
       if( wxFileExists( FileName ) )
       {
-         HelpSystem::ShowHelp(this, FileName, wxEmptyString);
+         HelpSystem::ShowHelp(this, FileName, wxEmptyString, false);
          return;
       }
       else

src/widgets/NumericTextCtrl.cpp

@@ -596,6 +596,7 @@ return theArray.Get();
       (NumericConverter::Type type)
    {
       switch (type) {
+         default:
          case NumericConverter::TIME:
             return TimeConverterFormats();
          case NumericConverter::FREQUENCY: