turned zarby 3bpp to 8bpp code into a routine

src/application/Data/rom.h

@@ -30,6 +30,7 @@ class ROM {
   void LoadFromFile(const std::string& path);
   std::vector<tile8> ExtractTiles(Graphics::TilePreset& preset);
   Graphics::SNESPalette ExtractPalette(Graphics::TilePreset& preset);
+  uchar* SNES3bppTo8bppSheet(uchar *sheet_buffer_in);
 
   uint32_t GetRomPosition(int direct_addr, uint snes_addr) const;
   inline uchar* GetRawData() { return current_rom_; }
@@ -54,6 +55,8 @@ class ROM {
   std::shared_ptr<uchar> rom_ptr_;
   std::unordered_map<unsigned int, std::shared_ptr<uchar[2048]>>
       decompressed_sheets;
+
+  const uchar bitmmask[8] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01};
 };
 
 }  // namespace Data