Remove unused variables

src/app/cmd/add_palette.h

@@ -51,7 +51,6 @@ namespace cmd {
     }
 
   private:
-    frame_t m_frame;
     std::stringstream m_stream;
   };
 

src/app/cmd/copy_frame.h

@@ -43,7 +43,6 @@ namespace cmd {
   private:
     frame_t m_fromFrame;
     frame_t m_newFrame;
-    bool m_firstTime;
   };
 
 } // namespace cmd

src/app/commands/cmd_mask_content.cpp

@@ -65,8 +65,6 @@ void MaskContentCommand::onExecute(Context* context)
 {
   ContextWriter writer(context);
   Document* document(writer.document());
-  Sprite* sprite(writer.sprite());
-  Layer* layer = writer.layer();
   Cel* cel = writer.cel(); // Get current cel (can be NULL)
   if (!cel)
     return;

src/app/transaction.cpp

@@ -34,7 +34,6 @@ using namespace doc;
 
 Transaction::Transaction(Context* ctx, const std::string& label, Modification modification)
   : m_ctx(ctx)
-  , m_modification(modification)
   , m_cmds(NULL)
 {
   DocumentLocation location = m_ctx->activeLocation();

src/app/transaction.h

@@ -73,7 +73,6 @@ namespace app {
     Context* m_ctx;
     DocumentUndo* m_undo;
     CmdTransaction* m_cmds;
-    Modification m_modification;
   };
 
 } // namespace app

src/render/render.cpp

@@ -415,10 +415,6 @@ void Render::renderLayer(
   if (!scaled_func)
     return;
 
-  const LayerImage* background = m_sprite->backgroundLayer();
-  bool need_checked_bg = (background != NULL ? !background->isVisible(): true);
-  color_t bg_color = 0;
-
   m_globalOpacity = 255;
   renderLayer(layer, dstImage, area,
     frame, Zoom(1, 1), scaled_func,