Prettifyed the code exploiting inheritance rules

added missing comma, added missing `override`

--HG--
branch : minor

src/modules/image/magpie/CompressedImageData.cpp

@@ -82,7 +82,7 @@ CompressedImageData::CompressedImageData(const CompressedImageData &c)
 	}
 }
 
-Data *CompressedImageData::clone() const
+CompressedImageData *CompressedImageData::clone() const
 {
 	return new CompressedImageData(*this);
 }

src/modules/image/magpie/CompressedImageData.h

@@ -44,7 +44,7 @@ public:
 	CompressedImageData(const CompressedImageData &c);
 	virtual ~CompressedImageData();
 
-	virtual Data *clone() const;
+	virtual CompressedImageData *clone() const;
 }; // CompressedImageData
 
 } // magpie

src/modules/image/magpie/ImageData.cpp

@@ -103,7 +103,7 @@ ImageData::~ImageData()
 		handler->release();
 }
 
-Data *ImageData::clone() const
+ImageData *ImageData::clone() const
 {
 	return new ImageData(*this);
 }

src/modules/image/magpie/ImageData.h

@@ -45,7 +45,7 @@ public:
 	ImageData(const ImageData &c);
 	virtual ~ImageData();
 
-	virtual Data *clone() const;
+	virtual ImageData *clone() const;
 	// Implements image::ImageData.
 	virtual love::filesystem::FileData *encode(EncodedFormat encodedFormat, const char *filename);