(svn r10092) -Codechange: code-seperated the spriteloader and blitter from the rest of the code

-Add: make it possible to pick your own blitter (-b <blitter>, -h for overview)
-Add: added a new optimized 8bpp blitter (default, caches sprites of all zoom-levels)
-Add: added a debug 8bpp blitter and a very slow normal 8bpp blitter

src/spriteloader/spriteloader.hpp

@@ -0,0 +1,34 @@
+/* $Id$ */
+
+/** @file spriteloader.hpp */
+
+#ifndef SPRITELOADER_HPP
+#define SPRITELOADER_HPP
+
+class SpriteLoader {
+public:
+	struct CommonPixel {
+		uint8 r;  ///< Red-channel
+		uint8 g;  ///< Green-channel
+		uint8 b;  ///< Blue-channel
+		uint8 a;  ///< Alpha-channel
+		uint8 m;  ///< Remap-channel
+	};
+
+	struct Sprite {
+		uint16 height;                   ///< Height of the sprite
+		uint16 width;                    ///< Width of the sprite
+		int16 x_offs;                    ///< The x-offset of where the sprite will be drawn
+		int16 y_offs;                    ///< The y-offset of where the sprite will be drawn
+		SpriteLoader::CommonPixel *data; ///< The sprite itself
+	};
+
+	/**
+	 * Load a sprite from the disk and return a sprite struct which is the same for all loaders.
+	 */
+	virtual bool LoadSprite(SpriteLoader::Sprite *sprite, uint32 file_pos) = 0;
+
+	virtual ~SpriteLoader() { }
+};
+
+#endif /* SPRITELOADER_HPP */